Sanders wrote in message ...
Until such time as Sanders has something of substance to contribute,
I withdraw.

Don't withdraw because of me. There are things others want/need from you!

You minsunderstand, I am withdrawing NOT from the group, but from
the invective-laden thread.

I am sure you are not even close to the way I misinterpeted your post
and it it was miscommunication between us that got out of hand.

I am not going to post here again, so you have no need to worry about
any contradictions to your theory of how a "good" speaker should
reproduce sound accurately.

Again, you misrepresent my words. I NEVER said it was "my" theory.
I gave you a set of specific citations in the hope that, like any
diligent practitioner or even some moderately interested in the topic,
you'd reference those citations as well as pursue follow-ons.

Instead, you choose to represent this as "my" theory. Tell me, but
how is this misrepresentation in any way fair?

Engineers and technicians will always see things from different viewpoints

IE: Do "electrons" move or do the "holes" move in electronics.

Does each description lead to wildy different predictions of
conduction? If they do, at least one of them has to be wrong. If
they don't, they are equivalent in the domains in which they work.

It was your theory of "experts" and how you treated other "experts" on
other fields that set it off.

IE: urban ledgend with no reference to back it up. Religous experts
saying the world was flat, etc.

My suggestion, Sanders, is that you consult a book on world religions.
While some western religions have accepted a spherical earth model
for a long time, western eligions have NOT been the dominant
philosophical model in the world.

The thing about the smaller wire was how mfg will cut corners in
production of loudspeakers that the end consumer never sees.

Why have 12g wire to the box and use 16g from the speaker terminal to
the woofer? The speaker mfg saves $$$ by using 16g instead of 12g.

That was just to say how the best designs get compromised in production
for the consumers.

But you have failed utterly to answer the question: what is the
TECHNICAL shortcoming to using a smaller gauge wire inside a woofer.
The economic advantage you cite is extraordinarily minor. Let's assume
the length of wire between the woofer and the terminal is 16 inches
long. How much money is saved by using 16 gauge instead of 12 gauge?
Well, a look at a number of distributor web sites for 16 and 12 gauge
two-conductor stranded PVC insulated wire shows costs in the realm of
$0.07/ft for 16 gauage and $0.18/ft for 12 gauge.

Now, in our hypothetical speaker, that means a cost of about 10 cents
for the 16 gauge and 24 cents for the 12 gauge, a difference, per
cabinet of 12 cents. Even considering a typical 4:1 effective cost
markup between material cost and recommended retail price, that's
less than a dollar impact on the RETAIL cost of a pair of speakers.
Now, I would argue that such small difference does NOT constitute a
strong economic incentive for going to smaller gauge wire. And, in fact,
having been a consultant to a number of loudspeaker system manufacturers,
I can tell you that this cost difference is, indeed, NOT a point of
concern to any of these manufacturers UNLESS they're econimic situation
is SO marginal as to put the entire company into jeoprady.

Beyond that, why is cutting cost, in and of itself, a bad thing? That's
a nonsensical position to take, I would posit. If it can be shown that
if part costs 24 cents and an equivalent part costs 10 cents, why does
it NOT make sense to use the 10 cent part? It increases the profit margin
to the manufacturer, provides room for adjusting the final price if that
accomodates the customer. Unless it can be shown that the 10 cent part
impacts the PERFORMANCE of the speaker in a deleterious fashion, what
is the motivation for NOT using that part?

So, now that I have provided some factual data to support the counter
to your assertion that they are doing it to cut costs, or most certainly
suggested that cost does not seem to be the determing factor, we must now
turn to the TECHNICAL side of your assert, at which point I repeat my
question, precisely as I asked it:

what do you think the effect "smaller wire" will have on the
performance of a loudspeaker?

This, in essence, boils the question down to a purely technical one.
One in which facts can be presented, evaluated and either supported
or refuted ONLY on the TECHNICAL merits of the argument, NOT on the
personalities or whose "instructors" are better or anything.

Again, you made the original assertion,

Things such as poor quality x-over components and smaller wire
size to cut final costs.

and I ask, what is the effect on the TECHNICAL PERFORMANCE of the
wire size, which you have now constrained to be the difference
between 16 guage and 12 gauge connecting the speaker terminal to
the woofer? The question is as simple as that.

Hint: for others interested in analyzing the situation, here's
the relevant data for your enlightenment: 16 gauge copper has
a DC resistance of 0.00402 ohms/ft, while 12 gauge has a DC
resistance of 0.00159 ohms/ft. If relevant, the fusing current
of the two are 117 amperes (16 gauge) and 235 amperes (12 gauge)
Assume a nominal 8 ohm woofer whose voice coil DC resistance is
6.25 ohms. Additionally consider as well a nominal 4 ohm woofer
with a DC resistance of 3.4 ohms. Assume an in-enclosure system
Qtc of 0.707 with a Qec of 0.89 under the conditons of Rg = 0.

You made it sound like you were very educated, like it was an ego thing
of "I am a Doctor", and a know it all about all things you discussed as
an expert, that was why the bs about the "Wright" Brothers came back.

It was purely BS, indeed. You focussed NOT on the TECHNICAL matters
being discussed, but on the fact that I type VERY fast and occasionally
make simple typographic errors.

I still disagree with you about the spider being stiff, as its purpose
is to keep the voice coil in the proper horizontal tolerances for
movement inside the magnetic field gap.

You may disagree all you want, and until you have the factual data to
support your position, it's merely one of unsubstantiated opinion.

I have, in fact, design MANY woofers and tweeters in my career,
INCLUDING, interestingly enough, a number that your friend Mr. Gold
purchased. I have measured many, many thousands of drivers, and have
a stock of driver components, including spiders and surrounds, on hand
from a number of component manufacturers specifically to provide
factual information to my clients.

I have DONE the experiment that shows the opposite of your assertion
to be the case. In it's simplest form, the hypothesis is thus:

Permise #1: The fundamental mechanical resonance of a woofer is
determined by the moving mass of the driver Mms and the
mechanical stiffness of the driver Kms as:

Fs = (2 pi sqrt(Mms/Kms)^-1

Premise #2: Given two parallel mechanical stiffness, the surround
stiffness Ksurr and the spider stiffness Kspid the total
resulting stiffness is:

Kms = Ksurr + Kspid

Please note that these two premises are not unique to loudspeakers, but
are describer by the generalm physics of mechanical harmonic oscillators.

From these two premises we can derive a third:

Premise #3: removing one or the otherv suspension components
from the driver will change the total stiffness of the driver
and thus its resonant frequency in proportion to the square
root of magnitude of the stiffness removed.

Now, unless you are willing to challenge these fundamental premises,
I suggest we proceed directly to my hypothesis:

Hypothesis: The centering spider provides the dominant mechanical
stiffness in most modern-day high-quality woofers. Therefore,
if one removes hust the spider, the resonant frequency should
drop by a factor significantly larger than if one were to remove
just the suspension.

Now this is completely equivalent to saying that such a driver built
without a spider will have a lower resonant frequency than the same
built without a suspension. Certainly neither constitute a viable
driver, since you have centering issues in both cases, but, as an
experiment to test the hypothesis, it's a completely valid set of
methods.

(of course, both ignore the far more direct method of measuring
stiffness directly, which what all of this is actually based
upon. But since most people do not have access to an inventory
of speaker components, the "removal" method is what remains.

Now, the hypothetical rubber meets the physical reality road. After
having conducted precisely this experiment, quite literally, HUNDREDS
of times, the result is that in a typical high-quality woofer, the
mechanical stiffness of the spider is at minimum TWICE that of the
surround and more typically on the order of 3-4 times that of the
surround. This is born out by the fact that removing the spider
results in a drop in resonaont frequency by as much as a factor of 2,
more typically on the order of about 1/2 an octave, while removing just
the surround results in a decrease in resonant frequency of only about
10%,

Unless you are willing and ready to propose a heretofore unknown
mechanism, the data quite stringly supports the hypothesis that it is
the spider that is the source of most of the mechanical stiffness in
most high-quality woofers these days.

The vertical movement of the spider should be as "loose as a goose" and
offer no resistance to the voice coil's desire to move.

That may be your assumption, but, alas, the data suggests quite the
contrary. 25 years ago I heald the same opinion, until the data showed
how wrong that opinion was.

This desire of no resistance for the voice coil movement is why better
woofers also have vented coils so the air pressure is taken out of the
equation, which I am sure you could quote how it affects the speaker
movement and I can't. JBL engineers must do it for a reason.

There are, in fact, several reasons why poles are vented:

1. The total displacement volume of the air behind the dustcap is
quite large for even small excursions. Thus, the resulting
large proportional changes in it's volume are often sufficient
to extend the compression beyond adiabatically linear compression.

But while the compression RATIO is large, the total volume
compressed is small, and thus does not materially affect the
total system stiffness.

2. In high-power applications that one often finds JBL woofers used
form venting the pole piece dramatically improves air cooling of
the voice coil by substantially increasing the colume of air
continuously moved through the gap.

3. The pumping of air through the gap in a non-vented situation may
lead to extraneous noise and distortion.

Please refer to the work of Gander at JBL and others on this topic,
published in the mid 1980's in JAES.

It is also noted that you failed to address the technicalm points I
raised about the role of enclosure to driver compliance ratios in
tuning vented systems, a hallmark foundation of the Thiele/Small
model. You may certainly choose to continue to ignore it, I was merely
challenging, on a technical basis, the technical validity of your
assertion regarding the suitability of driver compliance to reflex
implementations.

Sanders wrote in message ...
Until such time as Sanders has something of substance to contribute,
I withdraw.

Don't withdraw because of me. There are things others want/need from you!

You minsunderstand, I am withdrawing NOT from the group, but from
the invective-laden thread.

I am sure you are not even close to the way I misinterpeted your post
and it it was miscommunication between us that got out of hand.

I am not going to post here again, so you have no need to worry about
any contradictions to your theory of how a "good" speaker should
reproduce sound accurately.

Again, you misrepresent my words. I NEVER said it was "my" theory.
I gave you a set of specific citations in the hope that, like any
diligent practitioner or even some moderately interested in the topic,
you'd reference those citations as well as pursue follow-ons.

Instead, you choose to represent this as "my" theory. Tell me, but
how is this misrepresentation in any way fair?

Engineers and technicians will always see things from different viewpoints

IE: Do "electrons" move or do the "holes" move in electronics.

Does each description lead to wildy different predictions of
conduction? If they do, at least one of them has to be wrong. If
they don't, they are equivalent in the domains in which they work.

It was your theory of "experts" and how you treated other "experts" on
other fields that set it off.

IE: urban ledgend with no reference to back it up. Religous experts
saying the world was flat, etc.

My suggestion, Sanders, is that you consult a book on world religions.
While some western religions have accepted a spherical earth model
for a long time, western eligions have NOT been the dominant
philosophical model in the world.

The thing about the smaller wire was how mfg will cut corners in
production of loudspeakers that the end consumer never sees.

Why have 12g wire to the box and use 16g from the speaker terminal to
the woofer? The speaker mfg saves $$$ by using 16g instead of 12g.

That was just to say how the best designs get compromised in production
for the consumers.

But you have failed utterly to answer the question: what is the
TECHNICAL shortcoming to using a smaller gauge wire inside a woofer.
The economic advantage you cite is extraordinarily minor. Let's assume
the length of wire between the woofer and the terminal is 16 inches
long. How much money is saved by using 16 gauge instead of 12 gauge?
Well, a look at a number of distributor web sites for 16 and 12 gauge
two-conductor stranded PVC insulated wire shows costs in the realm of
$0.07/ft for 16 gauage and $0.18/ft for 12 gauge.

Now, in our hypothetical speaker, that means a cost of about 10 cents
for the 16 gauge and 24 cents for the 12 gauge, a difference, per
cabinet of 12 cents. Even considering a typical 4:1 effective cost
markup between material cost and recommended retail price, that's
less than a dollar impact on the RETAIL cost of a pair of speakers.
Now, I would argue that such small difference does NOT constitute a
strong economic incentive for going to smaller gauge wire. And, in fact,
having been a consultant to a number of loudspeaker system manufacturers,
I can tell you that this cost difference is, indeed, NOT a point of
concern to any of these manufacturers UNLESS they're econimic situation
is SO marginal as to put the entire company into jeoprady.

Beyond that, why is cutting cost, in and of itself, a bad thing? That's
a nonsensical position to take, I would posit. If it can be shown that
if part costs 24 cents and an equivalent part costs 10 cents, why does
it NOT make sense to use the 10 cent part? It increases the profit margin
to the manufacturer, provides room for adjusting the final price if that
accomodates the customer. Unless it can be shown that the 10 cent part
impacts the PERFORMANCE of the speaker in a deleterious fashion, what
is the motivation for NOT using that part?

So, now that I have provided some factual data to support the counter
to your assertion that they are doing it to cut costs, or most certainly
suggested that cost does not seem to be the determing factor, we must now
turn to the TECHNICAL side of your assert, at which point I repeat my
question, precisely as I asked it:

what do you think the effect "smaller wire" will have on the
performance of a loudspeaker?

This, in essence, boils the question down to a purely technical one.
One in which facts can be presented, evaluated and either supported
or refuted ONLY on the TECHNICAL merits of the argument, NOT on the
personalities or whose "instructors" are better or anything.

Again, you made the original assertion,

Things such as poor quality x-over components and smaller wire
size to cut final costs.

and I ask, what is the effect on the TECHNICAL PERFORMANCE of the
wire size, which you have now constrained to be the difference
between 16 guage and 12 gauge connecting the speaker terminal to
the woofer? The question is as simple as that.

Hint: for others interested in analyzing the situation, here's
the relevant data for your enlightenment: 16 gauge copper has
a DC resistance of 0.00402 ohms/ft, while 12 gauge has a DC
resistance of 0.00159 ohms/ft. If relevant, the fusing current
of the two are 117 amperes (16 gauge) and 235 amperes (12 gauge)
Assume a nominal 8 ohm woofer whose voice coil DC resistance is
6.25 ohms. Additionally consider as well a nominal 4 ohm woofer
with a DC resistance of 3.4 ohms. Assume an in-enclosure system
Qtc of 0.707 with a Qec of 0.89 under the conditons of Rg = 0.

You made it sound like you were very educated, like it was an ego thing
of "I am a Doctor", and a know it all about all things you discussed as
an expert, that was why the bs about the "Wright" Brothers came back.

It was purely BS, indeed. You focussed NOT on the TECHNICAL matters
being discussed, but on the fact that I type VERY fast and occasionally
make simple typographic errors.

I still disagree with you about the spider being stiff, as its purpose
is to keep the voice coil in the proper horizontal tolerances for
movement inside the magnetic field gap.

You may disagree all you want, and until you have the factual data to
support your position, it's merely one of unsubstantiated opinion.

I have, in fact, design MANY woofers and tweeters in my career,
INCLUDING, interestingly enough, a number that your friend Mr. Gold
purchased. I have measured many, many thousands of drivers, and have
a stock of driver components, including spiders and surrounds, on hand
from a number of component manufacturers specifically to provide
factual information to my clients.

I have DONE the experiment that shows the opposite of your assertion
to be the case. In it's simplest form, the hypothesis is thus:

Permise #1: The fundamental mechanical resonance of a woofer is
determined by the moving mass of the driver Mms and the
mechanical stiffness of the driver Kms as:

Fs = (2 pi sqrt(Mms/Kms)^-1

Premise #2: Given two parallel mechanical stiffness, the surround
stiffness Ksurr and the spider stiffness Kspid the total
resulting stiffness is:

Kms = Ksurr + Kspid

Please note that these two premises are not unique to loudspeakers, but
are describer by the generalm physics of mechanical harmonic oscillators.

From these two premises we can derive a third:

Premise #3: removing one or the otherv suspension components
from the driver will change the total stiffness of the driver
and thus its resonant frequency in proportion to the square
root of magnitude of the stiffness removed.

Now, unless you are willing to challenge these fundamental premises,
I suggest we proceed directly to my hypothesis:

Hypothesis: The centering spider provides the dominant mechanical
stiffness in most modern-day high-quality woofers. Therefore,
if one removes hust the spider, the resonant frequency should
drop by a factor significantly larger than if one were to remove
just the suspension.

Now this is completely equivalent to saying that such a driver built
without a spider will have a lower resonant frequency than the same
built without a suspension. Certainly neither constitute a viable
driver, since you have centering issues in both cases, but, as an
experiment to test the hypothesis, it's a completely valid set of
methods.

(of course, both ignore the far more direct method of measuring
stiffness directly, which what all of this is actually based
upon. But since most people do not have access to an inventory
of speaker components, the "removal" method is what remains.

Now, the hypothetical rubber meets the physical reality road. After
having conducted precisely this experiment, quite literally, HUNDREDS
of times, the result is that in a typical high-quality woofer, the
mechanical stiffness of the spider is at minimum TWICE that of the
surround and more typically on the order of 3-4 times that of the
surround. This is born out by the fact that removing the spider
results in a drop in resonaont frequency by as much as a factor of 2,
more typically on the order of about 1/2 an octave, while removing just
the surround results in a decrease in resonant frequency of only about
10%,

Unless you are willing and ready to propose a heretofore unknown
mechanism, the data quite stringly supports the hypothesis that it is
the spider that is the source of most of the mechanical stiffness in
most high-quality woofers these days.

The vertical movement of the spider should be as "loose as a goose" and
offer no resistance to the voice coil's desire to move.

That may be your assumption, but, alas, the data suggests quite the
contrary. 25 years ago I heald the same opinion, until the data showed
how wrong that opinion was.

This desire of no resistance for the voice coil movement is why better
woofers also have vented coils so the air pressure is taken out of the
equation, which I am sure you could quote how it affects the speaker
movement and I can't. JBL engineers must do it for a reason.

There are, in fact, several reasons why poles are vented:

1. The total displacement volume of the air behind the dustcap is
quite large for even small excursions. Thus, the resulting
large proportional changes in it's volume are often sufficient
to extend the compression beyond adiabatically linear compression.

But while the compression RATIO is large, the total volume
compressed is small, and thus does not materially affect the
total system stiffness.

2. In high-power applications that one often finds JBL woofers used
form venting the pole piece dramatically improves air cooling of
the voice coil by substantially increasing the colume of air
continuously moved through the gap.

3. The pumping of air through the gap in a non-vented situation may
lead to extraneous noise and distortion.

Please refer to the work of Gander at JBL and others on this topic,
published in the mid 1980's in JAES.

It is also noted that you failed to address the technicalm points I
raised about the role of enclosure to driver compliance ratios in
tuning vented systems, a hallmark foundation of the Thiele/Small
model. You may certainly choose to continue to ignore it, I was merely
challenging, on a technical basis, the technical validity of your
assertion regarding the suitability of driver compliance to reflex
implementations.

You minsunderstand, I am withdrawing NOT from the group, but from
the invective-laden thread.

With much apologies on my part to you Dick! I was very wrong in my
behavior to you!

I would never have been that way with a real person!

I am not saying you are not a real person, but referring to the
difference between physical and electronic, so communicating
electronically gave me no right to be rude either.

My parents raised me to be very polite, not to be jerkish, as I was to you.

Once again I am sorry for how I handled the post with you!


Instead, you choose to represent this as "my" theory. Tell me, but
how is this misrepresentation in any way fair?

By your theory, I meant ALL the new knowledge that you have acquired,
and I am sure that you have come up with new theories now that bypass
the knowledge of people who had constructed theories before you about
the subject back in the mid 1900.

Does each description lead to wildy different predictions of
conduction?

No, but back at Purdue, while learning electronics, engineers and
technicians looked at schematics differently. I never understood why
they were designed for holes, but we were taught that electrons moved

My suggestion, Sanders, is that you consult a book on world religions.
While some western religions have accepted a spherical earth model
for a long time, western eligions have NOT been the dominant
philosophical model in the world.

Would not the "religious experts" at that time also of been the
"scientific experts", due to limited availability of the masses to
achieve education? Education was usually only for nobility based
heritage. So religious and scientific would of been about the same
connotation of knowing the "facts" of that day.

That was just to say how the best designs get compromised in production
for the consumers.

I will still say that there are corners cut in production that differ
from the engineers original design being done. Not just in electronics,
but many things getting produced. I have seen it in building
construction of new homes where blueprints get modified on site.


But you have failed utterly to answer the question: what is the
TECHNICAL shortcoming to using a smaller gauge wire inside a woofer.

If I understand this correctly, you are saying that the size of the wire
from the amp to the speaker and the from the terminal to the woofer
doesn't matter.

If this is the truth, and I am assuming it is because you say so and it
is not a slam, why is 12g wire pushed so heavily as the best speaker
wire to use?

I could understand the less resistance being a factor in extremely long
runs, but for 20ft, would it matter?

This is a true question, not a slam to your knowledge!

I know that solid wire has less inductance than stranded so the highs
should be transferred better.

In your opinion, what size wire, and should it be solid or stranded, for
both amp to speaker connection, and also be used for internal connections?


what do you think the effect "smaller wire" will have on the
performance of a loudspeaker?

Alas, what I was "informed" to "inform" those I sold systems to. Notice
how informed is quoted so as to point out it is not my assumption, but
what I was told was true. As you have pointed out, the resistance
difference is negligible.

Hint: for others interested in analyzing the situation, here's
the relevant data for your enlightenment: 16 gauge copper has
a DC resistance of 0.00402 ohms/ft, while 12 gauge has a DC
resistance of 0.00159 ohms/ft. If relevant, the fusing current
of the two are 117 amperes (16 gauge) and 235 amperes (12 gauge)
Assume a nominal 8 ohm woofer whose voice coil DC resistance is
6.25 ohms. Additionally consider as well a nominal 4 ohm woofer
with a DC resistance of 3.4 ohms. Assume an in-enclosure system
Qtc of 0.707 with a Qec of 0.89 under the conditons of Rg = 0.


It was purely BS, indeed.
And I have apologized to you for those comments!

being discussed, but on the fact that I type VERY fast and occasionally
make simple typographic errors.

I can't spell worth a crap, let alone adding the typos to it, so I end
up using spell check a lot to catch my errors. My English instructors
at Purdue, and now my current programming instructors when I have to
write papers, have bitten me so many times, I couldn't count the times I
misused the wrong words spelled "write", but the wrong meaning in a
sentence. Points off again on this paper John - lol. I do understand.


I have, in fact, design MANY woofers and tweeters in my career,
INCLUDING, interestingly enough, a number that your friend Mr. Gold
purchased.

Some of these assertions I received from him, believing him to be an
"expert" as he knew more than me about the subject.

Curious, did you do the design on the GS 8,10,and 12 DVC speakers?


Kms = Ksurr + Kspid


Now, unless you are willing to challenge these fundamental premises,
I suggest we proceed directly to my hypothesis:

Hypothesis: The centering spider provides the dominant mechanical
stiffness in most modern-day high-quality woofers. Therefore,
if one removes hust the spider, the resonant frequency should
drop by a factor significantly larger than if one were to remove
just the suspension.

You lost me on the "significantly larger" when the above formula gives
equal weight to both the surround and the spider.

Not being a jerk, what am I missing between the formula and your
hypothesis of the spider having more "weight" in the equation?


Now, the hypothetical rubber meets the physical reality road. After
having conducted precisely this experiment, quite literally, HUNDREDS
of times, the result is that in a typical high-quality woofer, the
mechanical stiffness of the spider is at minimum TWICE that of the
surround and more typically on the order of 3-4 times that of the
surround. This is born out by the fact that removing the spider
results in a drop in resonaont frequency by as much as a factor of 2,
more typically on the order of about 1/2 an octave, while removing just
the surround results in a decrease in resonant frequency of only about
10%,

Proof that YOU have come up with a new theory that is more accurate than
the above formula through trial and error!

Kms = Ksurr + 3.5(Kspid) if I remember my algebra correctly.

Is this measurement of the 3-4 times on a new spider vs a spider that
has been "broken in" and has lost some stiffness? Would it even matter
in the resonant freq. when constructing a box if the spider is given a
"work out" before being installed? Or was this just sales hype I was
told as truth?


Unless you are willing and ready to propose a heretofore unknown
mechanism, the data quite stringly supports the hypothesis that it is
the spider that is the source of most of the mechanical stiffness in
most high-quality woofers these days.

What of the speakers in the 70's, which is where most of my "knowledge"
came from? Why were speakers like AR and Advent not ported back then?
Were their spiders not built as today's speaker's spiders? What am I
missing here?

The vertical movement of the spider should be as "loose as a goose" and
offer no resistance to the voice coil's desire to move.


That may be your assumption, but, alas, the data suggests quite the
contrary. 25 years ago I heald the same opinion, until the data showed
how wrong that opinion was.

Dating my knowledge would be back to the 70's as my starting point also.

These assumptions came from the fact that a speaker is a motor and the
spider was the "bearings" of the motor and the less resistance in the
bearings, the better the motor would perform.


This desire of no resistance for the voice coil movement is why better
woofers also have vented coils so the air pressure is taken out of the
equation, which I am sure you could quote how it affects the speaker
movement and I can't. JBL engineers must do it for a reason.


There are, in fact, several reasons why poles are vented:

1. The total displacement volume of the air behind the dustcap is
quite large for even small excursions. Thus, the resulting
large proportional changes in it's volume are often sufficient
to extend the compression beyond adiabatically linear compression.

Is there a reason dust caps are not designed to breathe - air molecules
are much smaller than dust particles? Is it more important for the dust
cap to act as part of the cone to move air forward than the resistance
of the air underneath the cap being compressed?

But while the compression RATIO is large, the total volume
compressed is small, and thus does not materially affect the
total system stiffness.

2. In high-power applications that one often finds JBL woofers used
form venting the pole piece dramatically improves air cooling of
the voice coil by substantially increasing the colume of air
continuously moved through the gap.

3. The pumping of air through the gap in a non-vented situation may
lead to extraneous noise and distortion.

So from this I gather that it was more for voice coil cooling at high
power use than the air compression having an effect on the response of
the speaker?

Under low to medium power, I doubt that the first or third statement
would even matter and was more sales hype we were told, more than
distortion actually being audible or a change in linear response then?

Please refer to the work of Gander at JBL and others on this topic,
published in the mid 1980's in JAES.

By this time period, I had to leave the audio/music business and got
into data processing because I didn't make enough money to support a
family. Computers could pay for a family and those places had health
insurance.


It is also noted that you failed to address the technicalm points I
raised about the role of enclosure to driver compliance ratios in
tuning vented systems, a hallmark foundation of the Thiele/Small
model. You may certainly choose to continue to ignore it, I was merely
challenging, on a technical basis, the technical validity of your
assertion regarding the suitability of driver compliance to reflex
implementations.

I can't give a technical reason to you and I wish I could have a formula
to quote to back up what my ears heard. The ported, rolled suspension,
speakers (mid 70's) just did not have the "snap" on acoustic bass, or
drums, that the sealed ones did. The ported JBL and EV speakers did
have the "snap" and were rigid surrounds.

The only advantage that I "knew" at the time was the lower freq.
response in a smaller box size, when a speaker was ported.

If you have a reason, or even a theory, why my ears heard this
difference, I would be very pleased to know.

Also, what is your opinion of "compound loaded" speakers being used for
subs. The hype was that you could go just as low with 1/2 the box size.

If true, then how would the port parameters change from using a single
driver as the driver mass/resistance would now be doubled for the
enclosure? Would it be "Spk1 + Spk2" or "Spk1 * Spk2" in the equations
involved?

I hope this post proves I am willing to "relearn" what I once thought
was the "truth" about "rolled" vs "rigid" suspension among other things
like wire and how it affects the sound.

Once again Dick, I am sorry for the crap I threw at you!

Thanks,

John

You minsunderstand, I am withdrawing NOT from the group, but from
the invective-laden thread.

With much apologies on my part to you Dick! I was very wrong in my
behavior to you!

I would never have been that way with a real person!

I am not saying you are not a real person, but referring to the
difference between physical and electronic, so communicating
electronically gave me no right to be rude either.

My parents raised me to be very polite, not to be jerkish, as I was to you.

Once again I am sorry for how I handled the post with you!


Instead, you choose to represent this as "my" theory. Tell me, but
how is this misrepresentation in any way fair?

By your theory, I meant ALL the new knowledge that you have acquired,
and I am sure that you have come up with new theories now that bypass
the knowledge of people who had constructed theories before you about
the subject back in the mid 1900.

Does each description lead to wildy different predictions of
conduction?

No, but back at Purdue, while learning electronics, engineers and
technicians looked at schematics differently. I never understood why
they were designed for holes, but we were taught that electrons moved

My suggestion, Sanders, is that you consult a book on world religions.
While some western religions have accepted a spherical earth model
for a long time, western eligions have NOT been the dominant
philosophical model in the world.

Would not the "religious experts" at that time also of been the
"scientific experts", due to limited availability of the masses to
achieve education? Education was usually only for nobility based
heritage. So religious and scientific would of been about the same
connotation of knowing the "facts" of that day.

That was just to say how the best designs get compromised in production
for the consumers.

I will still say that there are corners cut in production that differ
from the engineers original design being done. Not just in electronics,
but many things getting produced. I have seen it in building
construction of new homes where blueprints get modified on site.


But you have failed utterly to answer the question: what is the
TECHNICAL shortcoming to using a smaller gauge wire inside a woofer.

If I understand this correctly, you are saying that the size of the wire
from the amp to the speaker and the from the terminal to the woofer
doesn't matter.

If this is the truth, and I am assuming it is because you say so and it
is not a slam, why is 12g wire pushed so heavily as the best speaker
wire to use?

I could understand the less resistance being a factor in extremely long
runs, but for 20ft, would it matter?

This is a true question, not a slam to your knowledge!

I know that solid wire has less inductance than stranded so the highs
should be transferred better.

In your opinion, what size wire, and should it be solid or stranded, for
both amp to speaker connection, and also be used for internal connections?


what do you think the effect "smaller wire" will have on the
performance of a loudspeaker?

Alas, what I was "informed" to "inform" those I sold systems to. Notice
how informed is quoted so as to point out it is not my assumption, but
what I was told was true. As you have pointed out, the resistance
difference is negligible.

Hint: for others interested in analyzing the situation, here's
the relevant data for your enlightenment: 16 gauge copper has
a DC resistance of 0.00402 ohms/ft, while 12 gauge has a DC
resistance of 0.00159 ohms/ft. If relevant, the fusing current
of the two are 117 amperes (16 gauge) and 235 amperes (12 gauge)
Assume a nominal 8 ohm woofer whose voice coil DC resistance is
6.25 ohms. Additionally consider as well a nominal 4 ohm woofer
with a DC resistance of 3.4 ohms. Assume an in-enclosure system
Qtc of 0.707 with a Qec of 0.89 under the conditons of Rg = 0.


It was purely BS, indeed.
And I have apologized to you for those comments!

being discussed, but on the fact that I type VERY fast and occasionally
make simple typographic errors.

I can't spell worth a crap, let alone adding the typos to it, so I end
up using spell check a lot to catch my errors. My English instructors
at Purdue, and now my current programming instructors when I have to
write papers, have bitten me so many times, I couldn't count the times I
misused the wrong words spelled "write", but the wrong meaning in a
sentence. Points off again on this paper John - lol. I do understand.


I have, in fact, design MANY woofers and tweeters in my career,
INCLUDING, interestingly enough, a number that your friend Mr. Gold
purchased.

Some of these assertions I received from him, believing him to be an
"expert" as he knew more than me about the subject.

Curious, did you do the design on the GS 8,10,and 12 DVC speakers?


Kms = Ksurr + Kspid


Now, unless you are willing to challenge these fundamental premises,
I suggest we proceed directly to my hypothesis:

Hypothesis: The centering spider provides the dominant mechanical
stiffness in most modern-day high-quality woofers. Therefore,
if one removes hust the spider, the resonant frequency should
drop by a factor significantly larger than if one were to remove
just the suspension.

You lost me on the "significantly larger" when the above formula gives
equal weight to both the surround and the spider.

Not being a jerk, what am I missing between the formula and your
hypothesis of the spider having more "weight" in the equation?


Now, the hypothetical rubber meets the physical reality road. After
having conducted precisely this experiment, quite literally, HUNDREDS
of times, the result is that in a typical high-quality woofer, the
mechanical stiffness of the spider is at minimum TWICE that of the
surround and more typically on the order of 3-4 times that of the
surround. This is born out by the fact that removing the spider
results in a drop in resonaont frequency by as much as a factor of 2,
more typically on the order of about 1/2 an octave, while removing just
the surround results in a decrease in resonant frequency of only about
10%,

Proof that YOU have come up with a new theory that is more accurate than
the above formula through trial and error!

Kms = Ksurr + 3.5(Kspid) if I remember my algebra correctly.

Is this measurement of the 3-4 times on a new spider vs a spider that
has been "broken in" and has lost some stiffness? Would it even matter
in the resonant freq. when constructing a box if the spider is given a
"work out" before being installed? Or was this just sales hype I was
told as truth?


Unless you are willing and ready to propose a heretofore unknown
mechanism, the data quite stringly supports the hypothesis that it is
the spider that is the source of most of the mechanical stiffness in
most high-quality woofers these days.

What of the speakers in the 70's, which is where most of my "knowledge"
came from? Why were speakers like AR and Advent not ported back then?
Were their spiders not built as today's speaker's spiders? What am I
missing here?

The vertical movement of the spider should be as "loose as a goose" and
offer no resistance to the voice coil's desire to move.


That may be your assumption, but, alas, the data suggests quite the
contrary. 25 years ago I heald the same opinion, until the data showed
how wrong that opinion was.

Dating my knowledge would be back to the 70's as my starting point also.

These assumptions came from the fact that a speaker is a motor and the
spider was the "bearings" of the motor and the less resistance in the
bearings, the better the motor would perform.


This desire of no resistance for the voice coil movement is why better
woofers also have vented coils so the air pressure is taken out of the
equation, which I am sure you could quote how it affects the speaker
movement and I can't. JBL engineers must do it for a reason.


There are, in fact, several reasons why poles are vented:

1. The total displacement volume of the air behind the dustcap is
quite large for even small excursions. Thus, the resulting
large proportional changes in it's volume are often sufficient
to extend the compression beyond adiabatically linear compression.

Is there a reason dust caps are not designed to breathe - air molecules
are much smaller than dust particles? Is it more important for the dust
cap to act as part of the cone to move air forward than the resistance
of the air underneath the cap being compressed?

But while the compression RATIO is large, the total volume
compressed is small, and thus does not materially affect the
total system stiffness.

2. In high-power applications that one often finds JBL woofers used
form venting the pole piece dramatically improves air cooling of
the voice coil by substantially increasing the colume of air
continuously moved through the gap.

3. The pumping of air through the gap in a non-vented situation may
lead to extraneous noise and distortion.

So from this I gather that it was more for voice coil cooling at high
power use than the air compression having an effect on the response of
the speaker?

Under low to medium power, I doubt that the first or third statement
would even matter and was more sales hype we were told, more than
distortion actually being audible or a change in linear response then?

Please refer to the work of Gander at JBL and others on this topic,
published in the mid 1980's in JAES.

By this time period, I had to leave the audio/music business and got
into data processing because I didn't make enough money to support a
family. Computers could pay for a family and those places had health
insurance.


It is also noted that you failed to address the technicalm points I
raised about the role of enclosure to driver compliance ratios in
tuning vented systems, a hallmark foundation of the Thiele/Small
model. You may certainly choose to continue to ignore it, I was merely
challenging, on a technical basis, the technical validity of your
assertion regarding the suitability of driver compliance to reflex
implementations.

I can't give a technical reason to you and I wish I could have a formula
to quote to back up what my ears heard. The ported, rolled suspension,
speakers (mid 70's) just did not have the "snap" on acoustic bass, or
drums, that the sealed ones did. The ported JBL and EV speakers did
have the "snap" and were rigid surrounds.

The only advantage that I "knew" at the time was the lower freq.
response in a smaller box size, when a speaker was ported.

If you have a reason, or even a theory, why my ears heard this
difference, I would be very pleased to know.

Also, what is your opinion of "compound loaded" speakers being used for
subs. The hype was that you could go just as low with 1/2 the box size.

If true, then how would the port parameters change from using a single
driver as the driver mass/resistance would now be doubled for the
enclosure? Would it be "Spk1 + Spk2" or "Spk1 * Spk2" in the equations
involved?

I hope this post proves I am willing to "relearn" what I once thought
was the "truth" about "rolled" vs "rigid" suspension among other things
like wire and how it affects the sound.

Once again Dick, I am sorry for the crap I threw at you!

Thanks,

John

You minsunderstand, I am withdrawing NOT from the group, but from
the invective-laden thread.

With much apologies on my part to you Dick! I was very wrong in my
behavior to you!

I would never have been that way with a real person!

I am not saying you are not a real person, but referring to the
difference between physical and electronic, so communicating
electronically gave me no right to be rude either.

My parents raised me to be very polite, not to be jerkish, as I was to you.

Once again I am sorry for how I handled the post with you!


Instead, you choose to represent this as "my" theory. Tell me, but
how is this misrepresentation in any way fair?

By your theory, I meant ALL the new knowledge that you have acquired,
and I am sure that you have come up with new theories now that bypass
the knowledge of people who had constructed theories before you about
the subject back in the mid 1900.

Does each description lead to wildy different predictions of
conduction?

No, but back at Purdue, while learning electronics, engineers and
technicians looked at schematics differently. I never understood why
they were designed for holes, but we were taught that electrons moved

My suggestion, Sanders, is that you consult a book on world religions.
While some western religions have accepted a spherical earth model
for a long time, western eligions have NOT been the dominant
philosophical model in the world.

Would not the "religious experts" at that time also of been the
"scientific experts", due to limited availability of the masses to
achieve education? Education was usually only for nobility based
heritage. So religious and scientific would of been about the same
connotation of knowing the "facts" of that day.

That was just to say how the best designs get compromised in production
for the consumers.

I will still say that there are corners cut in production that differ
from the engineers original design being done. Not just in electronics,
but many things getting produced. I have seen it in building
construction of new homes where blueprints get modified on site.


But you have failed utterly to answer the question: what is the
TECHNICAL shortcoming to using a smaller gauge wire inside a woofer.

If I understand this correctly, you are saying that the size of the wire
from the amp to the speaker and the from the terminal to the woofer
doesn't matter.

If this is the truth, and I am assuming it is because you say so and it
is not a slam, why is 12g wire pushed so heavily as the best speaker
wire to use?

I could understand the less resistance being a factor in extremely long
runs, but for 20ft, would it matter?

This is a true question, not a slam to your knowledge!

I know that solid wire has less inductance than stranded so the highs
should be transferred better.

In your opinion, what size wire, and should it be solid or stranded, for
both amp to speaker connection, and also be used for internal connections?


what do you think the effect "smaller wire" will have on the
performance of a loudspeaker?

Alas, what I was "informed" to "inform" those I sold systems to. Notice
how informed is quoted so as to point out it is not my assumption, but
what I was told was true. As you have pointed out, the resistance
difference is negligible.

Hint: for others interested in analyzing the situation, here's
the relevant data for your enlightenment: 16 gauge copper has
a DC resistance of 0.00402 ohms/ft, while 12 gauge has a DC
resistance of 0.00159 ohms/ft. If relevant, the fusing current
of the two are 117 amperes (16 gauge) and 235 amperes (12 gauge)
Assume a nominal 8 ohm woofer whose voice coil DC resistance is
6.25 ohms. Additionally consider as well a nominal 4 ohm woofer
with a DC resistance of 3.4 ohms. Assume an in-enclosure system
Qtc of 0.707 with a Qec of 0.89 under the conditons of Rg = 0.


It was purely BS, indeed.
And I have apologized to you for those comments!

being discussed, but on the fact that I type VERY fast and occasionally
make simple typographic errors.

I can't spell worth a crap, let alone adding the typos to it, so I end
up using spell check a lot to catch my errors. My English instructors
at Purdue, and now my current programming instructors when I have to
write papers, have bitten me so many times, I couldn't count the times I
misused the wrong words spelled "write", but the wrong meaning in a
sentence. Points off again on this paper John - lol. I do understand.


I have, in fact, design MANY woofers and tweeters in my career,
INCLUDING, interestingly enough, a number that your friend Mr. Gold
purchased.

Some of these assertions I received from him, believing him to be an
"expert" as he knew more than me about the subject.

Curious, did you do the design on the GS 8,10,and 12 DVC speakers?


Kms = Ksurr + Kspid


Now, unless you are willing to challenge these fundamental premises,
I suggest we proceed directly to my hypothesis:

Hypothesis: The centering spider provides the dominant mechanical
stiffness in most modern-day high-quality woofers. Therefore,
if one removes hust the spider, the resonant frequency should
drop by a factor significantly larger than if one were to remove
just the suspension.

You lost me on the "significantly larger" when the above formula gives
equal weight to both the surround and the spider.

Not being a jerk, what am I missing between the formula and your
hypothesis of the spider having more "weight" in the equation?


Now, the hypothetical rubber meets the physical reality road. After
having conducted precisely this experiment, quite literally, HUNDREDS
of times, the result is that in a typical high-quality woofer, the
mechanical stiffness of the spider is at minimum TWICE that of the
surround and more typically on the order of 3-4 times that of the
surround. This is born out by the fact that removing the spider
results in a drop in resonaont frequency by as much as a factor of 2,
more typically on the order of about 1/2 an octave, while removing just
the surround results in a decrease in resonant frequency of only about
10%,

Proof that YOU have come up with a new theory that is more accurate than
the above formula through trial and error!

Kms = Ksurr + 3.5(Kspid) if I remember my algebra correctly.

Is this measurement of the 3-4 times on a new spider vs a spider that
has been "broken in" and has lost some stiffness? Would it even matter
in the resonant freq. when constructing a box if the spider is given a
"work out" before being installed? Or was this just sales hype I was
told as truth?


Unless you are willing and ready to propose a heretofore unknown
mechanism, the data quite stringly supports the hypothesis that it is
the spider that is the source of most of the mechanical stiffness in
most high-quality woofers these days.

What of the speakers in the 70's, which is where most of my "knowledge"
came from? Why were speakers like AR and Advent not ported back then?
Were their spiders not built as today's speaker's spiders? What am I
missing here?

The vertical movement of the spider should be as "loose as a goose" and
offer no resistance to the voice coil's desire to move.


That may be your assumption, but, alas, the data suggests quite the
contrary. 25 years ago I heald the same opinion, until the data showed
how wrong that opinion was.

Dating my knowledge would be back to the 70's as my starting point also.

These assumptions came from the fact that a speaker is a motor and the
spider was the "bearings" of the motor and the less resistance in the
bearings, the better the motor would perform.


This desire of no resistance for the voice coil movement is why better
woofers also have vented coils so the air pressure is taken out of the
equation, which I am sure you could quote how it affects the speaker
movement and I can't. JBL engineers must do it for a reason.


There are, in fact, several reasons why poles are vented:

1. The total displacement volume of the air behind the dustcap is
quite large for even small excursions. Thus, the resulting
large proportional changes in it's volume are often sufficient
to extend the compression beyond adiabatically linear compression.

Is there a reason dust caps are not designed to breathe - air molecules
are much smaller than dust particles? Is it more important for the dust
cap to act as part of the cone to move air forward than the resistance
of the air underneath the cap being compressed?

But while the compression RATIO is large, the total volume
compressed is small, and thus does not materially affect the
total system stiffness.

2. In high-power applications that one often finds JBL woofers used
form venting the pole piece dramatically improves air cooling of
the voice coil by substantially increasing the colume of air
continuously moved through the gap.

3. The pumping of air through the gap in a non-vented situation may
lead to extraneous noise and distortion.

So from this I gather that it was more for voice coil cooling at high
power use than the air compression having an effect on the response of
the speaker?

Under low to medium power, I doubt that the first or third statement
would even matter and was more sales hype we were told, more than
distortion actually being audible or a change in linear response then?

Please refer to the work of Gander at JBL and others on this topic,
published in the mid 1980's in JAES.

By this time period, I had to leave the audio/music business and got
into data processing because I didn't make enough money to support a
family. Computers could pay for a family and those places had health
insurance.


It is also noted that you failed to address the technicalm points I
raised about the role of enclosure to driver compliance ratios in
tuning vented systems, a hallmark foundation of the Thiele/Small
model. You may certainly choose to continue to ignore it, I was merely
challenging, on a technical basis, the technical validity of your
assertion regarding the suitability of driver compliance to reflex
implementations.

I can't give a technical reason to you and I wish I could have a formula
to quote to back up what my ears heard. The ported, rolled suspension,
speakers (mid 70's) just did not have the "snap" on acoustic bass, or
drums, that the sealed ones did. The ported JBL and EV speakers did
have the "snap" and were rigid surrounds.

The only advantage that I "knew" at the time was the lower freq.
response in a smaller box size, when a speaker was ported.

If you have a reason, or even a theory, why my ears heard this
difference, I would be very pleased to know.

Also, what is your opinion of "compound loaded" speakers being used for
subs. The hype was that you could go just as low with 1/2 the box size.

If true, then how would the port parameters change from using a single
driver as the driver mass/resistance would now be doubled for the
enclosure? Would it be "Spk1 + Spk2" or "Spk1 * Spk2" in the equations
involved?

I hope this post proves I am willing to "relearn" what I once thought
was the "truth" about "rolled" vs "rigid" suspension among other things
like wire and how it affects the sound.

Once again Dick, I am sorry for the crap I threw at you!

Thanks,

John

You minsunderstand, I am withdrawing NOT from the group, but from
the invective-laden thread.

With much apologies on my part to you Dick! I was very wrong in my
behavior to you!

I would never have been that way with a real person!

I am not saying you are not a real person, but referring to the
difference between physical and electronic, so communicating
electronically gave me no right to be rude either.

My parents raised me to be very polite, not to be jerkish, as I was to you.

Once again I am sorry for how I handled the post with you!


Instead, you choose to represent this as "my" theory. Tell me, but
how is this misrepresentation in any way fair?

By your theory, I meant ALL the new knowledge that you have acquired,
and I am sure that you have come up with new theories now that bypass
the knowledge of people who had constructed theories before you about
the subject back in the mid 1900.

Does each description lead to wildy different predictions of
conduction?

No, but back at Purdue, while learning electronics, engineers and
technicians looked at schematics differently. I never understood why
they were designed for holes, but we were taught that electrons moved

My suggestion, Sanders, is that you consult a book on world religions.
While some western religions have accepted a spherical earth model
for a long time, western eligions have NOT been the dominant
philosophical model in the world.

Would not the "religious experts" at that time also of been the
"scientific experts", due to limited availability of the masses to
achieve education? Education was usually only for nobility based
heritage. So religious and scientific would of been about the same
connotation of knowing the "facts" of that day.

That was just to say how the best designs get compromised in production
for the consumers.

I will still say that there are corners cut in production that differ
from the engineers original design being done. Not just in electronics,
but many things getting produced. I have seen it in building
construction of new homes where blueprints get modified on site.


But you have failed utterly to answer the question: what is the
TECHNICAL shortcoming to using a smaller gauge wire inside a woofer.

If I understand this correctly, you are saying that the size of the wire
from the amp to the speaker and the from the terminal to the woofer
doesn't matter.

If this is the truth, and I am assuming it is because you say so and it
is not a slam, why is 12g wire pushed so heavily as the best speaker
wire to use?

I could understand the less resistance being a factor in extremely long
runs, but for 20ft, would it matter?

This is a true question, not a slam to your knowledge!

I know that solid wire has less inductance than stranded so the highs
should be transferred better.

In your opinion, what size wire, and should it be solid or stranded, for
both amp to speaker connection, and also be used for internal connections?


what do you think the effect "smaller wire" will have on the
performance of a loudspeaker?

Alas, what I was "informed" to "inform" those I sold systems to. Notice
how informed is quoted so as to point out it is not my assumption, but
what I was told was true. As you have pointed out, the resistance
difference is negligible.

Hint: for others interested in analyzing the situation, here's
the relevant data for your enlightenment: 16 gauge copper has
a DC resistance of 0.00402 ohms/ft, while 12 gauge has a DC
resistance of 0.00159 ohms/ft. If relevant, the fusing current
of the two are 117 amperes (16 gauge) and 235 amperes (12 gauge)
Assume a nominal 8 ohm woofer whose voice coil DC resistance is
6.25 ohms. Additionally consider as well a nominal 4 ohm woofer
with a DC resistance of 3.4 ohms. Assume an in-enclosure system
Qtc of 0.707 with a Qec of 0.89 under the conditons of Rg = 0.


It was purely BS, indeed.
And I have apologized to you for those comments!

being discussed, but on the fact that I type VERY fast and occasionally
make simple typographic errors.

I can't spell worth a crap, let alone adding the typos to it, so I end
up using spell check a lot to catch my errors. My English instructors
at Purdue, and now my current programming instructors when I have to
write papers, have bitten me so many times, I couldn't count the times I
misused the wrong words spelled "write", but the wrong meaning in a
sentence. Points off again on this paper John - lol. I do understand.


I have, in fact, design MANY woofers and tweeters in my career,
INCLUDING, interestingly enough, a number that your friend Mr. Gold
purchased.

Some of these assertions I received from him, believing him to be an
"expert" as he knew more than me about the subject.

Curious, did you do the design on the GS 8,10,and 12 DVC speakers?


Kms = Ksurr + Kspid


Now, unless you are willing to challenge these fundamental premises,
I suggest we proceed directly to my hypothesis:

Hypothesis: The centering spider provides the dominant mechanical
stiffness in most modern-day high-quality woofers. Therefore,
if one removes hust the spider, the resonant frequency should
drop by a factor significantly larger than if one were to remove
just the suspension.

You lost me on the "significantly larger" when the above formula gives
equal weight to both the surround and the spider.

Not being a jerk, what am I missing between the formula and your
hypothesis of the spider having more "weight" in the equation?


Now, the hypothetical rubber meets the physical reality road. After
having conducted precisely this experiment, quite literally, HUNDREDS
of times, the result is that in a typical high-quality woofer, the
mechanical stiffness of the spider is at minimum TWICE that of the
surround and more typically on the order of 3-4 times that of the
surround. This is born out by the fact that removing the spider
results in a drop in resonaont frequency by as much as a factor of 2,
more typically on the order of about 1/2 an octave, while removing just
the surround results in a decrease in resonant frequency of only about
10%,

Proof that YOU have come up with a new theory that is more accurate than
the above formula through trial and error!

Kms = Ksurr + 3.5(Kspid) if I remember my algebra correctly.

Is this measurement of the 3-4 times on a new spider vs a spider that
has been "broken in" and has lost some stiffness? Would it even matter
in the resonant freq. when constructing a box if the spider is given a
"work out" before being installed? Or was this just sales hype I was
told as truth?


Unless you are willing and ready to propose a heretofore unknown
mechanism, the data quite stringly supports the hypothesis that it is
the spider that is the source of most of the mechanical stiffness in
most high-quality woofers these days.

What of the speakers in the 70's, which is where most of my "knowledge"
came from? Why were speakers like AR and Advent not ported back then?
Were their spiders not built as today's speaker's spiders? What am I
missing here?

The vertical movement of the spider should be as "loose as a goose" and
offer no resistance to the voice coil's desire to move.


That may be your assumption, but, alas, the data suggests quite the
contrary. 25 years ago I heald the same opinion, until the data showed
how wrong that opinion was.

Dating my knowledge would be back to the 70's as my starting point also.

These assumptions came from the fact that a speaker is a motor and the
spider was the "bearings" of the motor and the less resistance in the
bearings, the better the motor would perform.


This desire of no resistance for the voice coil movement is why better
woofers also have vented coils so the air pressure is taken out of the
equation, which I am sure you could quote how it affects the speaker
movement and I can't. JBL engineers must do it for a reason.


There are, in fact, several reasons why poles are vented:

1. The total displacement volume of the air behind the dustcap is
quite large for even small excursions. Thus, the resulting
large proportional changes in it's volume are often sufficient
to extend the compression beyond adiabatically linear compression.

Is there a reason dust caps are not designed to breathe - air molecules
are much smaller than dust particles? Is it more important for the dust
cap to act as part of the cone to move air forward than the resistance
of the air underneath the cap being compressed?

But while the compression RATIO is large, the total volume
compressed is small, and thus does not materially affect the
total system stiffness.

2. In high-power applications that one often finds JBL woofers used
form venting the pole piece dramatically improves air cooling of
the voice coil by substantially increasing the colume of air
continuously moved through the gap.

3. The pumping of air through the gap in a non-vented situation may
lead to extraneous noise and distortion.

So from this I gather that it was more for voice coil cooling at high
power use than the air compression having an effect on the response of
the speaker?

Under low to medium power, I doubt that the first or third statement
would even matter and was more sales hype we were told, more than
distortion actually being audible or a change in linear response then?

Please refer to the work of Gander at JBL and others on this topic,
published in the mid 1980's in JAES.

By this time period, I had to leave the audio/music business and got
into data processing because I didn't make enough money to support a
family. Computers could pay for a family and those places had health
insurance.


It is also noted that you failed to address the technicalm points I
raised about the role of enclosure to driver compliance ratios in
tuning vented systems, a hallmark foundation of the Thiele/Small
model. You may certainly choose to continue to ignore it, I was merely
challenging, on a technical basis, the technical validity of your
assertion regarding the suitability of driver compliance to reflex
implementations.

I can't give a technical reason to you and I wish I could have a formula
to quote to back up what my ears heard. The ported, rolled suspension,
speakers (mid 70's) just did not have the "snap" on acoustic bass, or
drums, that the sealed ones did. The ported JBL and EV speakers did
have the "snap" and were rigid surrounds.

The only advantage that I "knew" at the time was the lower freq.
response in a smaller box size, when a speaker was ported.

If you have a reason, or even a theory, why my ears heard this
difference, I would be very pleased to know.

Also, what is your opinion of "compound loaded" speakers being used for
subs. The hype was that you could go just as low with 1/2 the box size.

If true, then how would the port parameters change from using a single
driver as the driver mass/resistance would now be doubled for the
enclosure? Would it be "Spk1 + Spk2" or "Spk1 * Spk2" in the equations
involved?

I hope this post proves I am willing to "relearn" what I once thought
was the "truth" about "rolled" vs "rigid" suspension among other things
like wire and how it affects the sound.

Once again Dick, I am sorry for the crap I threw at you!

Thanks,

John

Sanders wrote in message ...

Instead, you choose to represent this as "my" theory. Tell me, but
how is this misrepresentation in any way fair?

By your theory, I meant ALL the new knowledge that you have acquired,
and I am sure that you have come up with new theories now that bypass
the knowledge of people who had constructed theories before you about
the subject back in the mid 1900.

No, you will find what I am saying is completely congruent with
most of the current body of knowledge on the topic. I never
represented it as "my" theory, and I would appreciate it if no
one else did, either.

Does each description lead to wildy different predictions of
conduction?

No,

Then there is no conflist between the two models. It's as simple
as that.

but back at Purdue, while learning electronics, engineers and
technicians looked at schematics differently. I never understood why
they were designed for holes, but we were taught that electrons moved

Because it was a convenient model. It really dates back to Benjamin
Franklin, who gave the two charges their names, and, inconveniently,
got it backwards.

As a matyter of clarification, I would suggest the dichotomy is more
between physicists and engineers/technicians.

My suggestion, Sanders, is that you consult a book on world religions.
While some western religions have accepted a spherical earth model
for a long time, western eligions have NOT been the dominant
philosophical model in the world.

Would not the "religious experts" at that time also of been the
"scientific experts", due to limited availability of the masses to
achieve education? Education was usually only for nobility based
heritage. So religious and scientific would of been about the same
connotation of knowing the "facts" of that day.

Well, that's directly contradicted precisely by the example of
Galileo, who was clearly a scientific expert. His theories were
based on observation, while those of the dominant power structure
were based on dogma. Because of the rigidity of that dogma, the
RC church was essentially left in the dust for a couple of centuries
as far as the development of the physical sciences were concerned.
Rather it flourished in the Low Countries and the British Isles with
the likes of Christian Hurgens and Isaac Newton, Edmond Halley and
the rest.

That was just to say how the best designs get compromised in production
for the consumers.

I will still say that there are corners cut in production that differ
from the engineers original design being done. Not just in electronics,
but many things getting produced. I have seen it in building
construction of new homes where blueprints get modified on site.


But you have failed utterly to answer the question: what is the
TECHNICAL shortcoming to using a smaller gauge wire inside a woofer.

If I understand this correctly, you are saying that the size of the wire
from the amp to the speaker and the from the terminal to the woofer
doesn't matter.

No, I never said any such thing. I asked a question.

If this is the truth, and I am assuming it is because you say so and it
is not a slam, why is 12g wire pushed so heavily as the best speaker
wire to use?

I never said it was, did I. I asked the question as to why you think
it should be one way or the other.

I could understand the less resistance being a factor in extremely long
runs, but for 20ft, would it matter?

This is a true question, not a slam to your knowledge!

I know that solid wire has less inductance than stranded so the highs
should be transferred better.

No, actually, taht's not true, not in ANY significant fashion.

In your opinion, what size wire, and should it be solid or stranded, for
both amp to speaker connection, and also be used for internal connections?

Not to be flippant, but the right size. And that's dependent upon the
application

what do you think the effect "smaller wire" will have on the
performance of a loudspeaker?

Alas, what I was "informed" to "inform" those I sold systems to. Notice
how informed is quoted so as to point out it is not my assumption, but
what I was told was true. As you have pointed out, the resistance
difference is negligible.

Aha! the beginnings of an actual questioning of an assumption!

I have, in fact, design MANY woofers and tweeters in my career,
INCLUDING, interestingly enough, a number that your friend Mr. Gold
purchased.

Some of these assertions I received from him, believing him to be an
"expert" as he knew more than me about the subject.

Curious, did you do the design on the GS 8,10,and 12 DVC speakers?

I did not, they are probably after my involvement with several of the
manufacturers that were supplying him.

Kms = Ksurr + Kspid

Now, unless you are willing to challenge these fundamental premises,
I suggest we proceed directly to my hypothesis:

Hypothesis: The centering spider provides the dominant mechanical
stiffness in most modern-day high-quality woofers. Therefore,
if one removes hust the spider, the resonant frequency should
drop by a factor significantly larger than if one were to remove
just the suspension.

You lost me on the "significantly larger" when the above formula gives
equal weight to both the surround and the spider.

Specifically, if the change in resonance by removing the spider is
larger that the change in resonance by moving the surround, that
says that the stiffness of the spider is greater than the stiffness
of the surround, it's that simple.

Not being a jerk, what am I missing between the formula and your
hypothesis of the spider having more "weight" in the equation?

Consider the following:

c = a + b

If a is larger than b, setting A to 0 will result in a greater change
in c than setting b to zero. For example:

c = 4 + 1

of, of course 5. If I change the 1 to a 0:

c = 4 + 0

the result is 4, a 20% reduction in the result. But if I change
the 4 to a 0:

c = 0 + 1

the result is 1, an 80% change in the resulting value. Thus, in
such a relation, the larger value clearly carries more "weight."

Now, the hypothetical rubber meets the physical reality road. After
having conducted precisely this experiment, quite literally, HUNDREDS
of times, the result is that in a typical high-quality woofer, the
mechanical stiffness of the spider is at minimum TWICE that of the
surround and more typically on the order of 3-4 times that of the
surround. This is born out by the fact that removing the spider
results in a drop in resonaont frequency by as much as a factor of 2,
more typically on the order of about 1/2 an octave, while removing just
the surround results in a decrease in resonant frequency of only about
10%,

Proof that YOU have come up with a new theory that is more accurate than
the above formula through trial and error!

This is absolutely NO theory whatsoever, it is simply a description
of the prevalant practice in the industry amongst a particular
domain of products.

Kms = Ksurr + 3.5(Kspid) if I remember my algebra correctly.

This is simply a summary of a particualr data set, nothing more,
nothing less.

Now, had I included the current default designs currently coming out
of the majority of Far East manufacturers, we'd find that, in fact,
the ration was significanrtly higher, on the order of 5 or 6 to one.

What's the theory behind that? There is no "theory." It's simply
because
many of these factories simpy do not care about the compliance. It's
their choice. No theory at all.

Is this measurement of the 3-4 times on a new spider vs a spider that
has been "broken in" and has lost some stiffness?

Yes. Generally, MOST of that "break-in" change is self-recovering,
i.e.,
Measure the driver resonance, break it in, it's lower, for sure, but
then lety it sit for a few minutes, and it's almost back up to where
it
was to begin with.

Would it even matter
in the resonant freq. when constructing a box if the spider is given a
"work out" before being installed?

Depends upon the type of enclosure and the system design. In the case
of true acoustic suspension designs, the cabinet is designed such that
the effective acoustic stiffness is at a minimum 3-4 times that of the
mechanical stiffness of the driver. Thus, since the enclosure
stiffness
dominates, changes in the driver stiffness (including unit-to-unit
variations, which are ineveitable) are relatively unimportant. In a
criticially tuned relfex system, it's more significant, because
generally
the enclosure stiffness and drievr stiffness are more proximal to one
another.

Or was this just sales hype I was
told as truth?

There may be some truth in it, but that truth got buried, it seems,
in the hype.

Unless you are willing and ready to propose a heretofore unknown
mechanism, the data quite stringly supports the hypothesis that it is
the spider that is the source of most of the mechanical stiffness in
most high-quality woofers these days.

What of the speakers in the 70's, which is where most of my "knowledge"
came from? Why were speakers like AR and Advent not ported back then?
Were their spiders not built as today's speaker's spiders? What am I
missing here?

You're missing the bigger pictu the correct notion that the
enclosure
and driver must work and be designed together as a system. Within the
limited realm of their expertise back then, that's precisely what AR
did: Vilchur knew, more on intuition then physics originally, that by
letting the ACOUSTIC stiffness by the dominating stiffness in the
system,
several hard to solve problems simply went away: linearity of the
suspension, unit-to-unit variations, and so on. The driver
manufacturing
technology of the time didn't allow for the tighter production
tolerances
necessary for properly desigtned reflexes, but that manufacturing
technology has advanced by leaps and bounds in the 45 years since AR
started their thing.

The vertical movement of the spider should be as "loose as a goose" and
offer no resistance to the voice coil's desire to move.
That may be your assumption, but, alas, the data suggests quite the
contrary. 25 years ago I heald the same opinion, until the data showed
how wrong that opinion was.

Dating my knowledge would be back to the 70's as my starting point also.

These assumptions came from the fact that a speaker is a motor and the
spider was the "bearings" of the motor and the less resistance in the
bearings, the better the motor would perform.

And here's where the temrinology is faling you. "Resistance" has one
implicit connotation, while "stiffness" is something else.

There are three quantities of relevance he resistance, stiffness
and mass. Two of these, stiffness and mass, are energy STORAGE
mechanisms: you start a mass moving, you give it a (kinetic) energy
equal to its mass times the velocity squared. You push on a stiffness
and hold it, you give it a (potential) energy equal to it's spring
constant times the distance squared (see the VERY interesting
similarity:

E = 1/2 mv^2

E = 1/2 kx^2

This energy you can get back again: try to slow the mass down, it
generates a force, let go of the spring, it bounces back. Both can
return the energy you put into them.

However, with the RESISTANCE, this is friction: put energy into a
resistance and it turns into heat. You can't turn the heat back into
usable motion: it's lost, never to come back in any useful form.

The resistance you feel when slowly pushing the cone is simply the
REACTIVE nature of the surround and spider pushing back. Let go,
and nearly all the enrgy you put into pushing it pushes the cone
back to where it started. That part that ISN'T returned causes the
suspension to heat up ever so slightly (and, interestingly enough,
makes the suspension a little looser: you have "broken it in." But
let it cool down and ...).

Now, INTUITIVELY, it seems like the stiffer the suspension, the less
efficient the speaker. But, sorry, intuition is wrong. This is because
the speaker does NOT work well at the sorts of speeds that you're
pushing at, it works at MUCH higher speeds. Push the cone in with your
hand as fats as you can. What sort of speed do you think you just
achieved? Maybe the equivalent of 1-2 inches per second. A speaker
moving back and forth 1/2" at a relatively low frequency of 20 Hz is
moving at a peak velocity of 63 inches per second, MUCH faster than
you could push it with your finger.

Secondly, you have only pushed the speaker one way. In operation
the speaker is really moving back and forth, accelerating one way,
then accelerating the other, back and forth. NOW, it's not the
STIFFNESS that's important, IT'S THE MASS OF THE CONE. Thus, when we
analyze the situation and develop a mathematical expression for
efficiency, we find there is NOTHING in that expression for the
suspension stiffness AT ALL: a dominant term is driver mass.

This desire of no resistance for the voice coil movement is why better
woofers also have vented coils so the air pressure is taken out of the
equation, which I am sure you could quote how it affects the speaker
movement and I can't. JBL engineers must do it for a reason.
There are, in fact, several reasons why poles are vented:

1. The total displacement volume of the air behind the dustcap is
quite large for even small excursions. Thus, the resulting
large proportional changes in it's volume are often sufficient
to extend the compression beyond adiabatically linear compression.

Is there a reason dust caps are not designed to breathe - air molecules
are much smaller than dust particles? Is it more important for the dust
cap to act as part of the cone to move air forward than the resistance
of the air underneath the cap being compressed?

No dustcap constitutes a REAL BIG "leak" in the system.

But while the compression RATIO is large, the total volume
compressed is small, and thus does not materially affect the
total system stiffness.

2. In high-power applications that one often finds JBL woofers used
form venting the pole piece dramatically improves air cooling of
the voice coil by substantially increasing the colume of air
continuously moved through the gap.

3. The pumping of air through the gap in a non-vented situation may
lead to extraneous noise and distortion.

So from this I gather that it was more for voice coil cooling at high
power use than the air compression having an effect on the response of
the speaker?

The compression effect is important, but not in terms of the direct
influence on driver stiffness, but more on secondary effects, such as
non-linearities and noises.

Under low to medium power, I doubt that the first or third statement
would even matter and was more sales hype we were told, more than
distortion actually being audible or a change in linear response then?

It's certainly measurable in extreme cases: it might be audible.

Remember that much of this work was done for sound-reinforcement
purposes, where the amounts of power being dissipated are HUGE.
Consider, for example, that atypical direct-radiator speaker
has an efficiency of maybe 1% or so. That means that every 100 watts
you put into the speaker, only 1 watt is converted to sound. Where
to you think the other 99 watts go?

HEAT!

And some of the speaker are driven with 1000 watts. Anything you can
do to get rid of that heat is going to make the life of the sound
guy much easier. You do NOT want to be crawling up a scaffolding to
replace a 15 inch woofer that burned out in the middle of a Metallica
concert.

It is also noted that you failed to address the technicalm points I
raised about the role of enclosure to driver compliance ratios in
tuning vented systems, a hallmark foundation of the Thiele/Small
model. You may certainly choose to continue to ignore it, I was merely
challenging, on a technical basis, the technical validity of your
assertion regarding the suitability of driver compliance to reflex
implementations.

I can't give a technical reason to you and I wish I could have a formula
to quote to back up what my ears heard. The ported, rolled suspension,
speakers (mid 70's) just did not have the "snap" on acoustic bass, or
drums, that the sealed ones did. The ported JBL and EV speakers did
have the "snap" and were rigid surrounds.

The only advantage that I "knew" at the time was the lower freq.
response in a smaller box size, when a speaker was ported.

And that goes back to the efficiency/enclosure size/bandwidth
relation:

n0 = kn Vb F3^3

If you have a reason, or even a theory, why my ears heard this
difference, I would be very pleased to know.

I have no theories for preference. None are needed. People like
what they

Also, what is your opinion of "compound loaded" speakers being used for
subs. The hype was that you could go just as low with 1/2 the box size.

and they are even MORE dependent upon variations in critical
parameters
such as compliance.

Once again Dick, I am sorry for the crap I threw at you!

Ain't learnin' fun?

Sanders wrote in message ...

Instead, you choose to represent this as "my" theory. Tell me, but
how is this misrepresentation in any way fair?

By your theory, I meant ALL the new knowledge that you have acquired,
and I am sure that you have come up with new theories now that bypass
the knowledge of people who had constructed theories before you about
the subject back in the mid 1900.

No, you will find what I am saying is completely congruent with
most of the current body of knowledge on the topic. I never
represented it as "my" theory, and I would appreciate it if no
one else did, either.

Does each description lead to wildy different predictions of
conduction?

No,

Then there is no conflist between the two models. It's as simple
as that.

but back at Purdue, while learning electronics, engineers and
technicians looked at schematics differently. I never understood why
they were designed for holes, but we were taught that electrons moved

Because it was a convenient model. It really dates back to Benjamin
Franklin, who gave the two charges their names, and, inconveniently,
got it backwards.

As a matyter of clarification, I would suggest the dichotomy is more
between physicists and engineers/technicians.

My suggestion, Sanders, is that you consult a book on world religions.
While some western religions have accepted a spherical earth model
for a long time, western eligions have NOT been the dominant
philosophical model in the world.

Would not the "religious experts" at that time also of been the
"scientific experts", due to limited availability of the masses to
achieve education? Education was usually only for nobility based
heritage. So religious and scientific would of been about the same
connotation of knowing the "facts" of that day.

Well, that's directly contradicted precisely by the example of
Galileo, who was clearly a scientific expert. His theories were
based on observation, while those of the dominant power structure
were based on dogma. Because of the rigidity of that dogma, the
RC church was essentially left in the dust for a couple of centuries
as far as the development of the physical sciences were concerned.
Rather it flourished in the Low Countries and the British Isles with
the likes of Christian Hurgens and Isaac Newton, Edmond Halley and
the rest.

That was just to say how the best designs get compromised in production
for the consumers.

I will still say that there are corners cut in production that differ
from the engineers original design being done. Not just in electronics,
but many things getting produced. I have seen it in building
construction of new homes where blueprints get modified on site.


But you have failed utterly to answer the question: what is the
TECHNICAL shortcoming to using a smaller gauge wire inside a woofer.

If I understand this correctly, you are saying that the size of the wire
from the amp to the speaker and the from the terminal to the woofer
doesn't matter.

No, I never said any such thing. I asked a question.

If this is the truth, and I am assuming it is because you say so and it
is not a slam, why is 12g wire pushed so heavily as the best speaker
wire to use?

I never said it was, did I. I asked the question as to why you think
it should be one way or the other.

I could understand the less resistance being a factor in extremely long
runs, but for 20ft, would it matter?

This is a true question, not a slam to your knowledge!

I know that solid wire has less inductance than stranded so the highs
should be transferred better.

No, actually, taht's not true, not in ANY significant fashion.

In your opinion, what size wire, and should it be solid or stranded, for
both amp to speaker connection, and also be used for internal connections?

Not to be flippant, but the right size. And that's dependent upon the
application

what do you think the effect "smaller wire" will have on the
performance of a loudspeaker?

Alas, what I was "informed" to "inform" those I sold systems to. Notice
how informed is quoted so as to point out it is not my assumption, but
what I was told was true. As you have pointed out, the resistance
difference is negligible.

Aha! the beginnings of an actual questioning of an assumption!

I have, in fact, design MANY woofers and tweeters in my career,
INCLUDING, interestingly enough, a number that your friend Mr. Gold
purchased.

Some of these assertions I received from him, believing him to be an
"expert" as he knew more than me about the subject.

Curious, did you do the design on the GS 8,10,and 12 DVC speakers?

I did not, they are probably after my involvement with several of the
manufacturers that were supplying him.

Kms = Ksurr + Kspid

Now, unless you are willing to challenge these fundamental premises,
I suggest we proceed directly to my hypothesis:

Hypothesis: The centering spider provides the dominant mechanical
stiffness in most modern-day high-quality woofers. Therefore,
if one removes hust the spider, the resonant frequency should
drop by a factor significantly larger than if one were to remove
just the suspension.

You lost me on the "significantly larger" when the above formula gives
equal weight to both the surround and the spider.

Specifically, if the change in resonance by removing the spider is
larger that the change in resonance by moving the surround, that
says that the stiffness of the spider is greater than the stiffness
of the surround, it's that simple.

Not being a jerk, what am I missing between the formula and your
hypothesis of the spider having more "weight" in the equation?

Consider the following:

c = a + b

If a is larger than b, setting A to 0 will result in a greater change
in c than setting b to zero. For example:

c = 4 + 1

of, of course 5. If I change the 1 to a 0:

c = 4 + 0

the result is 4, a 20% reduction in the result. But if I change
the 4 to a 0:

c = 0 + 1

the result is 1, an 80% change in the resulting value. Thus, in
such a relation, the larger value clearly carries more "weight."

Now, the hypothetical rubber meets the physical reality road. After
having conducted precisely this experiment, quite literally, HUNDREDS
of times, the result is that in a typical high-quality woofer, the
mechanical stiffness of the spider is at minimum TWICE that of the
surround and more typically on the order of 3-4 times that of the
surround. This is born out by the fact that removing the spider
results in a drop in resonaont frequency by as much as a factor of 2,
more typically on the order of about 1/2 an octave, while removing just
the surround results in a decrease in resonant frequency of only about
10%,

Proof that YOU have come up with a new theory that is more accurate than
the above formula through trial and error!

This is absolutely NO theory whatsoever, it is simply a description
of the prevalant practice in the industry amongst a particular
domain of products.

Kms = Ksurr + 3.5(Kspid) if I remember my algebra correctly.

This is simply a summary of a particualr data set, nothing more,
nothing less.

Now, had I included the current default designs currently coming out
of the majority of Far East manufacturers, we'd find that, in fact,
the ration was significanrtly higher, on the order of 5 or 6 to one.

What's the theory behind that? There is no "theory." It's simply
because
many of these factories simpy do not care about the compliance. It's
their choice. No theory at all.

Is this measurement of the 3-4 times on a new spider vs a spider that
has been "broken in" and has lost some stiffness?

Yes. Generally, MOST of that "break-in" change is self-recovering,
i.e.,
Measure the driver resonance, break it in, it's lower, for sure, but
then lety it sit for a few minutes, and it's almost back up to where
it
was to begin with.

Would it even matter
in the resonant freq. when constructing a box if the spider is given a
"work out" before being installed?

Depends upon the type of enclosure and the system design. In the case
of true acoustic suspension designs, the cabinet is designed such that
the effective acoustic stiffness is at a minimum 3-4 times that of the
mechanical stiffness of the driver. Thus, since the enclosure
stiffness
dominates, changes in the driver stiffness (including unit-to-unit
variations, which are ineveitable) are relatively unimportant. In a
criticially tuned relfex system, it's more significant, because
generally
the enclosure stiffness and drievr stiffness are more proximal to one
another.

Or was this just sales hype I was
told as truth?

There may be some truth in it, but that truth got buried, it seems,
in the hype.

Unless you are willing and ready to propose a heretofore unknown
mechanism, the data quite stringly supports the hypothesis that it is
the spider that is the source of most of the mechanical stiffness in
most high-quality woofers these days.

What of the speakers in the 70's, which is where most of my "knowledge"
came from? Why were speakers like AR and Advent not ported back then?
Were their spiders not built as today's speaker's spiders? What am I
missing here?

You're missing the bigger pictu the correct notion that the
enclosure
and driver must work and be designed together as a system. Within the
limited realm of their expertise back then, that's precisely what AR
did: Vilchur knew, more on intuition then physics originally, that by
letting the ACOUSTIC stiffness by the dominating stiffness in the
system,
several hard to solve problems simply went away: linearity of the
suspension, unit-to-unit variations, and so on. The driver
manufacturing
technology of the time didn't allow for the tighter production
tolerances
necessary for properly desigtned reflexes, but that manufacturing
technology has advanced by leaps and bounds in the 45 years since AR
started their thing.

The vertical movement of the spider should be as "loose as a goose" and
offer no resistance to the voice coil's desire to move.
That may be your assumption, but, alas, the data suggests quite the
contrary. 25 years ago I heald the same opinion, until the data showed
how wrong that opinion was.

Dating my knowledge would be back to the 70's as my starting point also.

These assumptions came from the fact that a speaker is a motor and the
spider was the "bearings" of the motor and the less resistance in the
bearings, the better the motor would perform.

And here's where the temrinology is faling you. "Resistance" has one
implicit connotation, while "stiffness" is something else.

There are three quantities of relevance he resistance, stiffness
and mass. Two of these, stiffness and mass, are energy STORAGE
mechanisms: you start a mass moving, you give it a (kinetic) energy
equal to its mass times the velocity squared. You push on a stiffness
and hold it, you give it a (potential) energy equal to it's spring
constant times the distance squared (see the VERY interesting
similarity:

E = 1/2 mv^2

E = 1/2 kx^2

This energy you can get back again: try to slow the mass down, it
generates a force, let go of the spring, it bounces back. Both can
return the energy you put into them.

However, with the RESISTANCE, this is friction: put energy into a
resistance and it turns into heat. You can't turn the heat back into
usable motion: it's lost, never to come back in any useful form.

The resistance you feel when slowly pushing the cone is simply the
REACTIVE nature of the surround and spider pushing back. Let go,
and nearly all the enrgy you put into pushing it pushes the cone
back to where it started. That part that ISN'T returned causes the
suspension to heat up ever so slightly (and, interestingly enough,
makes the suspension a little looser: you have "broken it in." But
let it cool down and ...).

Now, INTUITIVELY, it seems like the stiffer the suspension, the less
efficient the speaker. But, sorry, intuition is wrong. This is because
the speaker does NOT work well at the sorts of speeds that you're
pushing at, it works at MUCH higher speeds. Push the cone in with your
hand as fats as you can. What sort of speed do you think you just
achieved? Maybe the equivalent of 1-2 inches per second. A speaker
moving back and forth 1/2" at a relatively low frequency of 20 Hz is
moving at a peak velocity of 63 inches per second, MUCH faster than
you could push it with your finger.

Secondly, you have only pushed the speaker one way. In operation
the speaker is really moving back and forth, accelerating one way,
then accelerating the other, back and forth. NOW, it's not the
STIFFNESS that's important, IT'S THE MASS OF THE CONE. Thus, when we
analyze the situation and develop a mathematical expression for
efficiency, we find there is NOTHING in that expression for the
suspension stiffness AT ALL: a dominant term is driver mass.

This desire of no resistance for the voice coil movement is why better
woofers also have vented coils so the air pressure is taken out of the
equation, which I am sure you could quote how it affects the speaker
movement and I can't. JBL engineers must do it for a reason.
There are, in fact, several reasons why poles are vented:

1. The total displacement volume of the air behind the dustcap is
quite large for even small excursions. Thus, the resulting
large proportional changes in it's volume are often sufficient
to extend the compression beyond adiabatically linear compression.

Is there a reason dust caps are not designed to breathe - air molecules
are much smaller than dust particles? Is it more important for the dust
cap to act as part of the cone to move air forward than the resistance
of the air underneath the cap being compressed?

No dustcap constitutes a REAL BIG "leak" in the system.

But while the compression RATIO is large, the total volume
compressed is small, and thus does not materially affect the
total system stiffness.

2. In high-power applications that one often finds JBL woofers used
form venting the pole piece dramatically improves air cooling of
the voice coil by substantially increasing the colume of air
continuously moved through the gap.

3. The pumping of air through the gap in a non-vented situation may
lead to extraneous noise and distortion.

So from this I gather that it was more for voice coil cooling at high
power use than the air compression having an effect on the response of
the speaker?

The compression effect is important, but not in terms of the direct
influence on driver stiffness, but more on secondary effects, such as
non-linearities and noises.

Under low to medium power, I doubt that the first or third statement
would even matter and was more sales hype we were told, more than
distortion actually being audible or a change in linear response then?

It's certainly measurable in extreme cases: it might be audible.

Remember that much of this work was done for sound-reinforcement
purposes, where the amounts of power being dissipated are HUGE.
Consider, for example, that atypical direct-radiator speaker
has an efficiency of maybe 1% or so. That means that every 100 watts
you put into the speaker, only 1 watt is converted to sound. Where
to you think the other 99 watts go?

HEAT!

And some of the speaker are driven with 1000 watts. Anything you can
do to get rid of that heat is going to make the life of the sound
guy much easier. You do NOT want to be crawling up a scaffolding to
replace a 15 inch woofer that burned out in the middle of a Metallica
concert.

It is also noted that you failed to address the technicalm points I
raised about the role of enclosure to driver compliance ratios in
tuning vented systems, a hallmark foundation of the Thiele/Small
model. You may certainly choose to continue to ignore it, I was merely
challenging, on a technical basis, the technical validity of your
assertion regarding the suitability of driver compliance to reflex
implementations.

I can't give a technical reason to you and I wish I could have a formula
to quote to back up what my ears heard. The ported, rolled suspension,
speakers (mid 70's) just did not have the "snap" on acoustic bass, or
drums, that the sealed ones did. The ported JBL and EV speakers did
have the "snap" and were rigid surrounds.

The only advantage that I "knew" at the time was the lower freq.
response in a smaller box size, when a speaker was ported.

And that goes back to the efficiency/enclosure size/bandwidth
relation:

n0 = kn Vb F3^3

If you have a reason, or even a theory, why my ears heard this
difference, I would be very pleased to know.

I have no theories for preference. None are needed. People like
what they

Also, what is your opinion of "compound loaded" speakers being used for
subs. The hype was that you could go just as low with 1/2 the box size.

and they are even MORE dependent upon variations in critical
parameters
such as compliance.

Once again Dick, I am sorry for the crap I threw at you!

Ain't learnin' fun?

Sanders wrote in message ...

Instead, you choose to represent this as "my" theory. Tell me, but
how is this misrepresentation in any way fair?

By your theory, I meant ALL the new knowledge that you have acquired,
and I am sure that you have come up with new theories now that bypass
the knowledge of people who had constructed theories before you about
the subject back in the mid 1900.

No, you will find what I am saying is completely congruent with
most of the current body of knowledge on the topic. I never
represented it as "my" theory, and I would appreciate it if no
one else did, either.

Does each description lead to wildy different predictions of
conduction?

No,

Then there is no conflist between the two models. It's as simple
as that.

but back at Purdue, while learning electronics, engineers and
technicians looked at schematics differently. I never understood why
they were designed for holes, but we were taught that electrons moved

Because it was a convenient model. It really dates back to Benjamin
Franklin, who gave the two charges their names, and, inconveniently,
got it backwards.

As a matyter of clarification, I would suggest the dichotomy is more
between physicists and engineers/technicians.

My suggestion, Sanders, is that you consult a book on world religions.
While some western religions have accepted a spherical earth model
for a long time, western eligions have NOT been the dominant
philosophical model in the world.

Would not the "religious experts" at that time also of been the
"scientific experts", due to limited availability of the masses to
achieve education? Education was usually only for nobility based
heritage. So religious and scientific would of been about the same
connotation of knowing the "facts" of that day.

Well, that's directly contradicted precisely by the example of
Galileo, who was clearly a scientific expert. His theories were
based on observation, while those of the dominant power structure
were based on dogma. Because of the rigidity of that dogma, the
RC church was essentially left in the dust for a couple of centuries
as far as the development of the physical sciences were concerned.
Rather it flourished in the Low Countries and the British Isles with
the likes of Christian Hurgens and Isaac Newton, Edmond Halley and
the rest.

That was just to say how the best designs get compromised in production
for the consumers.

I will still say that there are corners cut in production that differ
from the engineers original design being done. Not just in electronics,
but many things getting produced. I have seen it in building
construction of new homes where blueprints get modified on site.


But you have failed utterly to answer the question: what is the
TECHNICAL shortcoming to using a smaller gauge wire inside a woofer.

If I understand this correctly, you are saying that the size of the wire
from the amp to the speaker and the from the terminal to the woofer
doesn't matter.

No, I never said any such thing. I asked a question.

If this is the truth, and I am assuming it is because you say so and it
is not a slam, why is 12g wire pushed so heavily as the best speaker
wire to use?

I never said it was, did I. I asked the question as to why you think
it should be one way or the other.

I could understand the less resistance being a factor in extremely long
runs, but for 20ft, would it matter?

This is a true question, not a slam to your knowledge!

I know that solid wire has less inductance than stranded so the highs
should be transferred better.

No, actually, taht's not true, not in ANY significant fashion.

In your opinion, what size wire, and should it be solid or stranded, for
both amp to speaker connection, and also be used for internal connections?

Not to be flippant, but the right size. And that's dependent upon the
application

what do you think the effect "smaller wire" will have on the
performance of a loudspeaker?

Alas, what I was "informed" to "inform" those I sold systems to. Notice
how informed is quoted so as to point out it is not my assumption, but
what I was told was true. As you have pointed out, the resistance
difference is negligible.

Aha! the beginnings of an actual questioning of an assumption!

I have, in fact, design MANY woofers and tweeters in my career,
INCLUDING, interestingly enough, a number that your friend Mr. Gold
purchased.

Some of these assertions I received from him, believing him to be an
"expert" as he knew more than me about the subject.

Curious, did you do the design on the GS 8,10,and 12 DVC speakers?

I did not, they are probably after my involvement with several of the
manufacturers that were supplying him.

Kms = Ksurr + Kspid

Now, unless you are willing to challenge these fundamental premises,
I suggest we proceed directly to my hypothesis:

Hypothesis: The centering spider provides the dominant mechanical
stiffness in most modern-day high-quality woofers. Therefore,
if one removes hust the spider, the resonant frequency should
drop by a factor significantly larger than if one were to remove
just the suspension.

You lost me on the "significantly larger" when the above formula gives
equal weight to both the surround and the spider.

Specifically, if the change in resonance by removing the spider is
larger that the change in resonance by moving the surround, that
says that the stiffness of the spider is greater than the stiffness
of the surround, it's that simple.

Not being a jerk, what am I missing between the formula and your
hypothesis of the spider having more "weight" in the equation?

Consider the following:

c = a + b

If a is larger than b, setting A to 0 will result in a greater change
in c than setting b to zero. For example:

c = 4 + 1

of, of course 5. If I change the 1 to a 0:

c = 4 + 0

the result is 4, a 20% reduction in the result. But if I change
the 4 to a 0:

c = 0 + 1

the result is 1, an 80% change in the resulting value. Thus, in
such a relation, the larger value clearly carries more "weight."

Now, the hypothetical rubber meets the physical reality road. After
having conducted precisely this experiment, quite literally, HUNDREDS
of times, the result is that in a typical high-quality woofer, the
mechanical stiffness of the spider is at minimum TWICE that of the
surround and more typically on the order of 3-4 times that of the
surround. This is born out by the fact that removing the spider
results in a drop in resonaont frequency by as much as a factor of 2,
more typically on the order of about 1/2 an octave, while removing just
the surround results in a decrease in resonant frequency of only about
10%,

Proof that YOU have come up with a new theory that is more accurate than
the above formula through trial and error!

This is absolutely NO theory whatsoever, it is simply a description
of the prevalant practice in the industry amongst a particular
domain of products.

Kms = Ksurr + 3.5(Kspid) if I remember my algebra correctly.

This is simply a summary of a particualr data set, nothing more,
nothing less.

Now, had I included the current default designs currently coming out
of the majority of Far East manufacturers, we'd find that, in fact,
the ration was significanrtly higher, on the order of 5 or 6 to one.

What's the theory behind that? There is no "theory." It's simply
because
many of these factories simpy do not care about the compliance. It's
their choice. No theory at all.

Is this measurement of the 3-4 times on a new spider vs a spider that
has been "broken in" and has lost some stiffness?

Yes. Generally, MOST of that "break-in" change is self-recovering,
i.e.,
Measure the driver resonance, break it in, it's lower, for sure, but
then lety it sit for a few minutes, and it's almost back up to where
it
was to begin with.

Would it even matter
in the resonant freq. when constructing a box if the spider is given a
"work out" before being installed?

Depends upon the type of enclosure and the system design. In the case
of true acoustic suspension designs, the cabinet is designed such that
the effective acoustic stiffness is at a minimum 3-4 times that of the
mechanical stiffness of the driver. Thus, since the enclosure
stiffness
dominates, changes in the driver stiffness (including unit-to-unit
variations, which are ineveitable) are relatively unimportant. In a
criticially tuned relfex system, it's more significant, because
generally
the enclosure stiffness and drievr stiffness are more proximal to one
another.

Or was this just sales hype I was
told as truth?

There may be some truth in it, but that truth got buried, it seems,
in the hype.

Unless you are willing and ready to propose a heretofore unknown
mechanism, the data quite stringly supports the hypothesis that it is
the spider that is the source of most of the mechanical stiffness in
most high-quality woofers these days.

What of the speakers in the 70's, which is where most of my "knowledge"
came from? Why were speakers like AR and Advent not ported back then?
Were their spiders not built as today's speaker's spiders? What am I
missing here?

You're missing the bigger pictu the correct notion that the
enclosure
and driver must work and be designed together as a system. Within the
limited realm of their expertise back then, that's precisely what AR
did: Vilchur knew, more on intuition then physics originally, that by
letting the ACOUSTIC stiffness by the dominating stiffness in the
system,
several hard to solve problems simply went away: linearity of the
suspension, unit-to-unit variations, and so on. The driver
manufacturing
technology of the time didn't allow for the tighter production
tolerances
necessary for properly desigtned reflexes, but that manufacturing
technology has advanced by leaps and bounds in the 45 years since AR
started their thing.

The vertical movement of the spider should be as "loose as a goose" and
offer no resistance to the voice coil's desire to move.
That may be your assumption, but, alas, the data suggests quite the
contrary. 25 years ago I heald the same opinion, until the data showed
how wrong that opinion was.

Dating my knowledge would be back to the 70's as my starting point also.

These assumptions came from the fact that a speaker is a motor and the
spider was the "bearings" of the motor and the less resistance in the
bearings, the better the motor would perform.

And here's where the temrinology is faling you. "Resistance" has one
implicit connotation, while "stiffness" is something else.

There are three quantities of relevance he resistance, stiffness
and mass. Two of these, stiffness and mass, are energy STORAGE
mechanisms: you start a mass moving, you give it a (kinetic) energy
equal to its mass times the velocity squared. You push on a stiffness
and hold it, you give it a (potential) energy equal to it's spring
constant times the distance squared (see the VERY interesting
similarity:

E = 1/2 mv^2

E = 1/2 kx^2

This energy you can get back again: try to slow the mass down, it
generates a force, let go of the spring, it bounces back. Both can
return the energy you put into them.

However, with the RESISTANCE, this is friction: put energy into a
resistance and it turns into heat. You can't turn the heat back into
usable motion: it's lost, never to come back in any useful form.

The resistance you feel when slowly pushing the cone is simply the
REACTIVE nature of the surround and spider pushing back. Let go,
and nearly all the enrgy you put into pushing it pushes the cone
back to where it started. That part that ISN'T returned causes the
suspension to heat up ever so slightly (and, interestingly enough,
makes the suspension a little looser: you have "broken it in." But
let it cool down and ...).

Now, INTUITIVELY, it seems like the stiffer the suspension, the less
efficient the speaker. But, sorry, intuition is wrong. This is because
the speaker does NOT work well at the sorts of speeds that you're
pushing at, it works at MUCH higher speeds. Push the cone in with your
hand as fats as you can. What sort of speed do you think you just
achieved? Maybe the equivalent of 1-2 inches per second. A speaker
moving back and forth 1/2" at a relatively low frequency of 20 Hz is
moving at a peak velocity of 63 inches per second, MUCH faster than
you could push it with your finger.

Secondly, you have only pushed the speaker one way. In operation
the speaker is really moving back and forth, accelerating one way,
then accelerating the other, back and forth. NOW, it's not the
STIFFNESS that's important, IT'S THE MASS OF THE CONE. Thus, when we
analyze the situation and develop a mathematical expression for
efficiency, we find there is NOTHING in that expression for the
suspension stiffness AT ALL: a dominant term is driver mass.

This desire of no resistance for the voice coil movement is why better
woofers also have vented coils so the air pressure is taken out of the
equation, which I am sure you could quote how it affects the speaker
movement and I can't. JBL engineers must do it for a reason.
There are, in fact, several reasons why poles are vented:

1. The total displacement volume of the air behind the dustcap is
quite large for even small excursions. Thus, the resulting
large proportional changes in it's volume are often sufficient
to extend the compression beyond adiabatically linear compression.

Is there a reason dust caps are not designed to breathe - air molecules
are much smaller than dust particles? Is it more important for the dust
cap to act as part of the cone to move air forward than the resistance
of the air underneath the cap being compressed?

No dustcap constitutes a REAL BIG "leak" in the system.

But while the compression RATIO is large, the total volume
compressed is small, and thus does not materially affect the
total system stiffness.

2. In high-power applications that one often finds JBL woofers used
form venting the pole piece dramatically improves air cooling of
the voice coil by substantially increasing the colume of air
continuously moved through the gap.

3. The pumping of air through the gap in a non-vented situation may
lead to extraneous noise and distortion.

So from this I gather that it was more for voice coil cooling at high
power use than the air compression having an effect on the response of
the speaker?

The compression effect is important, but not in terms of the direct
influence on driver stiffness, but more on secondary effects, such as
non-linearities and noises.

Under low to medium power, I doubt that the first or third statement
would even matter and was more sales hype we were told, more than
distortion actually being audible or a change in linear response then?

It's certainly measurable in extreme cases: it might be audible.

Remember that much of this work was done for sound-reinforcement
purposes, where the amounts of power being dissipated are HUGE.
Consider, for example, that atypical direct-radiator speaker
has an efficiency of maybe 1% or so. That means that every 100 watts
you put into the speaker, only 1 watt is converted to sound. Where
to you think the other 99 watts go?

HEAT!

And some of the speaker are driven with 1000 watts. Anything you can
do to get rid of that heat is going to make the life of the sound
guy much easier. You do NOT want to be crawling up a scaffolding to
replace a 15 inch woofer that burned out in the middle of a Metallica
concert.

It is also noted that you failed to address the technicalm points I
raised about the role of enclosure to driver compliance ratios in
tuning vented systems, a hallmark foundation of the Thiele/Small
model. You may certainly choose to continue to ignore it, I was merely
challenging, on a technical basis, the technical validity of your
assertion regarding the suitability of driver compliance to reflex
implementations.

I can't give a technical reason to you and I wish I could have a formula
to quote to back up what my ears heard. The ported, rolled suspension,
speakers (mid 70's) just did not have the "snap" on acoustic bass, or
drums, that the sealed ones did. The ported JBL and EV speakers did
have the "snap" and were rigid surrounds.

The only advantage that I "knew" at the time was the lower freq.
response in a smaller box size, when a speaker was ported.

And that goes back to the efficiency/enclosure size/bandwidth
relation:

n0 = kn Vb F3^3

If you have a reason, or even a theory, why my ears heard this
difference, I would be very pleased to know.

I have no theories for preference. None are needed. People like
what they

Also, what is your opinion of "compound loaded" speakers being used for
subs. The hype was that you could go just as low with 1/2 the box size.

and they are even MORE dependent upon variations in critical
parameters
such as compliance.

Once again Dick, I am sorry for the crap I threw at you!

Ain't learnin' fun?

Sanders wrote in message ...

Instead, you choose to represent this as "my" theory. Tell me, but
how is this misrepresentation in any way fair?

By your theory, I meant ALL the new knowledge that you have acquired,
and I am sure that you have come up with new theories now that bypass
the knowledge of people who had constructed theories before you about
the subject back in the mid 1900.

No, you will find what I am saying is completely congruent with
most of the current body of knowledge on the topic. I never
represented it as "my" theory, and I would appreciate it if no
one else did, either.

Does each description lead to wildy different predictions of
conduction?

No,

Then there is no conflist between the two models. It's as simple
as that.

but back at Purdue, while learning electronics, engineers and
technicians looked at schematics differently. I never understood why
they were designed for holes, but we were taught that electrons moved

Because it was a convenient model. It really dates back to Benjamin
Franklin, who gave the two charges their names, and, inconveniently,
got it backwards.

As a matyter of clarification, I would suggest the dichotomy is more
between physicists and engineers/technicians.

My suggestion, Sanders, is that you consult a book on world religions.
While some western religions have accepted a spherical earth model
for a long time, western eligions have NOT been the dominant
philosophical model in the world.

Would not the "religious experts" at that time also of been the
"scientific experts", due to limited availability of the masses to
achieve education? Education was usually only for nobility based
heritage. So religious and scientific would of been about the same
connotation of knowing the "facts" of that day.

Well, that's directly contradicted precisely by the example of
Galileo, who was clearly a scientific expert. His theories were
based on observation, while those of the dominant power structure
were based on dogma. Because of the rigidity of that dogma, the
RC church was essentially left in the dust for a couple of centuries
as far as the development of the physical sciences were concerned.
Rather it flourished in the Low Countries and the British Isles with
the likes of Christian Hurgens and Isaac Newton, Edmond Halley and
the rest.

That was just to say how the best designs get compromised in production
for the consumers.

I will still say that there are corners cut in production that differ
from the engineers original design being done. Not just in electronics,
but many things getting produced. I have seen it in building
construction of new homes where blueprints get modified on site.


But you have failed utterly to answer the question: what is the
TECHNICAL shortcoming to using a smaller gauge wire inside a woofer.

If I understand this correctly, you are saying that the size of the wire
from the amp to the speaker and the from the terminal to the woofer
doesn't matter.

No, I never said any such thing. I asked a question.

If this is the truth, and I am assuming it is because you say so and it
is not a slam, why is 12g wire pushed so heavily as the best speaker
wire to use?

I never said it was, did I. I asked the question as to why you think
it should be one way or the other.

I could understand the less resistance being a factor in extremely long
runs, but for 20ft, would it matter?

This is a true question, not a slam to your knowledge!

I know that solid wire has less inductance than stranded so the highs
should be transferred better.

No, actually, taht's not true, not in ANY significant fashion.

In your opinion, what size wire, and should it be solid or stranded, for
both amp to speaker connection, and also be used for internal connections?

Not to be flippant, but the right size. And that's dependent upon the
application

what do you think the effect "smaller wire" will have on the
performance of a loudspeaker?

Alas, what I was "informed" to "inform" those I sold systems to. Notice
how informed is quoted so as to point out it is not my assumption, but
what I was told was true. As you have pointed out, the resistance
difference is negligible.

Aha! the beginnings of an actual questioning of an assumption!

I have, in fact, design MANY woofers and tweeters in my career,
INCLUDING, interestingly enough, a number that your friend Mr. Gold
purchased.

Some of these assertions I received from him, believing him to be an
"expert" as he knew more than me about the subject.

Curious, did you do the design on the GS 8,10,and 12 DVC speakers?

I did not, they are probably after my involvement with several of the
manufacturers that were supplying him.

Kms = Ksurr + Kspid

Now, unless you are willing to challenge these fundamental premises,
I suggest we proceed directly to my hypothesis:

Hypothesis: The centering spider provides the dominant mechanical
stiffness in most modern-day high-quality woofers. Therefore,
if one removes hust the spider, the resonant frequency should
drop by a factor significantly larger than if one were to remove
just the suspension.

You lost me on the "significantly larger" when the above formula gives
equal weight to both the surround and the spider.

Specifically, if the change in resonance by removing the spider is
larger that the change in resonance by moving the surround, that
says that the stiffness of the spider is greater than the stiffness
of the surround, it's that simple.

Not being a jerk, what am I missing between the formula and your
hypothesis of the spider having more "weight" in the equation?

Consider the following:

c = a + b

If a is larger than b, setting A to 0 will result in a greater change
in c than setting b to zero. For example:

c = 4 + 1

of, of course 5. If I change the 1 to a 0:

c = 4 + 0

the result is 4, a 20% reduction in the result. But if I change
the 4 to a 0:

c = 0 + 1

the result is 1, an 80% change in the resulting value. Thus, in
such a relation, the larger value clearly carries more "weight."

Now, the hypothetical rubber meets the physical reality road. After
having conducted precisely this experiment, quite literally, HUNDREDS
of times, the result is that in a typical high-quality woofer, the
mechanical stiffness of the spider is at minimum TWICE that of the
surround and more typically on the order of 3-4 times that of the
surround. This is born out by the fact that removing the spider
results in a drop in resonaont frequency by as much as a factor of 2,
more typically on the order of about 1/2 an octave, while removing just
the surround results in a decrease in resonant frequency of only about
10%,

Proof that YOU have come up with a new theory that is more accurate than
the above formula through trial and error!

This is absolutely NO theory whatsoever, it is simply a description
of the prevalant practice in the industry amongst a particular
domain of products.

Kms = Ksurr + 3.5(Kspid) if I remember my algebra correctly.

This is simply a summary of a particualr data set, nothing more,
nothing less.

Now, had I included the current default designs currently coming out
of the majority of Far East manufacturers, we'd find that, in fact,
the ration was significanrtly higher, on the order of 5 or 6 to one.

What's the theory behind that? There is no "theory." It's simply
because
many of these factories simpy do not care about the compliance. It's
their choice. No theory at all.

Is this measurement of the 3-4 times on a new spider vs a spider that
has been "broken in" and has lost some stiffness?

Yes. Generally, MOST of that "break-in" change is self-recovering,
i.e.,
Measure the driver resonance, break it in, it's lower, for sure, but
then lety it sit for a few minutes, and it's almost back up to where
it
was to begin with.

Would it even matter
in the resonant freq. when constructing a box if the spider is given a
"work out" before being installed?

Depends upon the type of enclosure and the system design. In the case
of true acoustic suspension designs, the cabinet is designed such that
the effective acoustic stiffness is at a minimum 3-4 times that of the
mechanical stiffness of the driver. Thus, since the enclosure
stiffness
dominates, changes in the driver stiffness (including unit-to-unit
variations, which are ineveitable) are relatively unimportant. In a
criticially tuned relfex system, it's more significant, because
generally
the enclosure stiffness and drievr stiffness are more proximal to one
another.

Or was this just sales hype I was
told as truth?

There may be some truth in it, but that truth got buried, it seems,
in the hype.

Unless you are willing and ready to propose a heretofore unknown
mechanism, the data quite stringly supports the hypothesis that it is
the spider that is the source of most of the mechanical stiffness in
most high-quality woofers these days.

What of the speakers in the 70's, which is where most of my "knowledge"
came from? Why were speakers like AR and Advent not ported back then?
Were their spiders not built as today's speaker's spiders? What am I
missing here?

You're missing the bigger pictu the correct notion that the
enclosure
and driver must work and be designed together as a system. Within the
limited realm of their expertise back then, that's precisely what AR
did: Vilchur knew, more on intuition then physics originally, that by
letting the ACOUSTIC stiffness by the dominating stiffness in the
system,
several hard to solve problems simply went away: linearity of the
suspension, unit-to-unit variations, and so on. The driver
manufacturing
technology of the time didn't allow for the tighter production
tolerances
necessary for properly desigtned reflexes, but that manufacturing
technology has advanced by leaps and bounds in the 45 years since AR
started their thing.

The vertical movement of the spider should be as "loose as a goose" and
offer no resistance to the voice coil's desire to move.
That may be your assumption, but, alas, the data suggests quite the
contrary. 25 years ago I heald the same opinion, until the data showed
how wrong that opinion was.

Dating my knowledge would be back to the 70's as my starting point also.

These assumptions came from the fact that a speaker is a motor and the
spider was the "bearings" of the motor and the less resistance in the
bearings, the better the motor would perform.

And here's where the temrinology is faling you. "Resistance" has one
implicit connotation, while "stiffness" is something else.

There are three quantities of relevance he resistance, stiffness
and mass. Two of these, stiffness and mass, are energy STORAGE
mechanisms: you start a mass moving, you give it a (kinetic) energy
equal to its mass times the velocity squared. You push on a stiffness
and hold it, you give it a (potential) energy equal to it's spring
constant times the distance squared (see the VERY interesting
similarity:

E = 1/2 mv^2

E = 1/2 kx^2

This energy you can get back again: try to slow the mass down, it
generates a force, let go of the spring, it bounces back. Both can
return the energy you put into them.

However, with the RESISTANCE, this is friction: put energy into a
resistance and it turns into heat. You can't turn the heat back into
usable motion: it's lost, never to come back in any useful form.

The resistance you feel when slowly pushing the cone is simply the
REACTIVE nature of the surround and spider pushing back. Let go,
and nearly all the enrgy you put into pushing it pushes the cone
back to where it started. That part that ISN'T returned causes the
suspension to heat up ever so slightly (and, interestingly enough,
makes the suspension a little looser: you have "broken it in." But
let it cool down and ...).

Now, INTUITIVELY, it seems like the stiffer the suspension, the less
efficient the speaker. But, sorry, intuition is wrong. This is because
the speaker does NOT work well at the sorts of speeds that you're
pushing at, it works at MUCH higher speeds. Push the cone in with your
hand as fats as you can. What sort of speed do you think you just
achieved? Maybe the equivalent of 1-2 inches per second. A speaker
moving back and forth 1/2" at a relatively low frequency of 20 Hz is
moving at a peak velocity of 63 inches per second, MUCH faster than
you could push it with your finger.

Secondly, you have only pushed the speaker one way. In operation
the speaker is really moving back and forth, accelerating one way,
then accelerating the other, back and forth. NOW, it's not the
STIFFNESS that's important, IT'S THE MASS OF THE CONE. Thus, when we
analyze the situation and develop a mathematical expression for
efficiency, we find there is NOTHING in that expression for the
suspension stiffness AT ALL: a dominant term is driver mass.

This desire of no resistance for the voice coil movement is why better
woofers also have vented coils so the air pressure is taken out of the
equation, which I am sure you could quote how it affects the speaker
movement and I can't. JBL engineers must do it for a reason.
There are, in fact, several reasons why poles are vented:

1. The total displacement volume of the air behind the dustcap is
quite large for even small excursions. Thus, the resulting
large proportional changes in it's volume are often sufficient
to extend the compression beyond adiabatically linear compression.

Is there a reason dust caps are not designed to breathe - air molecules
are much smaller than dust particles? Is it more important for the dust
cap to act as part of the cone to move air forward than the resistance
of the air underneath the cap being compressed?

No dustcap constitutes a REAL BIG "leak" in the system.

But while the compression RATIO is large, the total volume
compressed is small, and thus does not materially affect the
total system stiffness.

2. In high-power applications that one often finds JBL woofers used
form venting the pole piece dramatically improves air cooling of
the voice coil by substantially increasing the colume of air
continuously moved through the gap.

3. The pumping of air through the gap in a non-vented situation may
lead to extraneous noise and distortion.

So from this I gather that it was more for voice coil cooling at high
power use than the air compression having an effect on the response of
the speaker?

The compression effect is important, but not in terms of the direct
influence on driver stiffness, but more on secondary effects, such as
non-linearities and noises.

Under low to medium power, I doubt that the first or third statement
would even matter and was more sales hype we were told, more than
distortion actually being audible or a change in linear response then?

It's certainly measurable in extreme cases: it might be audible.

Remember that much of this work was done for sound-reinforcement
purposes, where the amounts of power being dissipated are HUGE.
Consider, for example, that atypical direct-radiator speaker
has an efficiency of maybe 1% or so. That means that every 100 watts
you put into the speaker, only 1 watt is converted to sound. Where
to you think the other 99 watts go?

HEAT!

And some of the speaker are driven with 1000 watts. Anything you can
do to get rid of that heat is going to make the life of the sound
guy much easier. You do NOT want to be crawling up a scaffolding to
replace a 15 inch woofer that burned out in the middle of a Metallica
concert.

It is also noted that you failed to address the technicalm points I
raised about the role of enclosure to driver compliance ratios in
tuning vented systems, a hallmark foundation of the Thiele/Small
model. You may certainly choose to continue to ignore it, I was merely
challenging, on a technical basis, the technical validity of your
assertion regarding the suitability of driver compliance to reflex
implementations.

I can't give a technical reason to you and I wish I could have a formula
to quote to back up what my ears heard. The ported, rolled suspension,
speakers (mid 70's) just did not have the "snap" on acoustic bass, or
drums, that the sealed ones did. The ported JBL and EV speakers did
have the "snap" and were rigid surrounds.

The only advantage that I "knew" at the time was the lower freq.
response in a smaller box size, when a speaker was ported.

And that goes back to the efficiency/enclosure size/bandwidth
relation:

n0 = kn Vb F3^3

If you have a reason, or even a theory, why my ears heard this
difference, I would be very pleased to know.

I have no theories for preference. None are needed. People like
what they

Also, what is your opinion of "compound loaded" speakers being used for
subs. The hype was that you could go just as low with 1/2 the box size.

and they are even MORE dependent upon variations in critical
parameters
such as compliance.

Once again Dick, I am sorry for the crap I threw at you!

Ain't learnin' fun?

I never represented it as "my" theory, and I would appreciate it if no
one else did, either.

Sorry, I should of said your understanding and practical use of theory
instead of calling it your theory.

Because it was a convenient model. It really dates back to Benjamin
Franklin, who gave the two charges their names, and, inconveniently,
got it backwards.

As a matyter of clarification, I would suggest the dichotomy is more
between physicists and engineers/technicians.

That makes more sense about physics, considering how quantum mechanics
and Newtonian physics seem to disagree, but both are right.

An example being, is light a wave or consist of photons? Depends on
what you measure and look for.

The following was sniped because of length concerning the
religous/scientific "expert" validty thing for those new to this post - JS

Well, that's directly contradicted precisely by the example of
Galileo, who was clearly a scientific expert. His theories were
based on observation, while those of the dominant power structure
were based on dogma. Because of the rigidity of that dogma,

He faced possible torture and almost lost his head as I recall from
history because the pope did not like his refusal to stop his teachings.

If I understand this correctly, you are saying that the size of the wire
from the amp to the speaker and the from the terminal to the woofer
doesn't matter.

I never said it was, did I. I asked the question as to why you think
it should be one way or the other.

I will attempt to answer the question the best I can from previous info
in this thread.

Smaller wire would offer a higher resistance from the speaker box
terminal to the woofer, thus a loss in power from the amp to the woofer.

The assumption then being, that the wire size to the speaker box should
be the same size wire going to the woofer.

As I understand from your explinations of resistence differences between
wire sizes, the length of wire from the terminal to the woofer is so
short, the added resistance would be negligable for power loss
calculations and wire size differences was more of a sales hype than
reality based?

I know that solid wire has less inductance than stranded so the highs
should be transferred better.


No, actually, taht's not true, not in ANY significant fashion.

Sorry, but I got that assumption from another thread going on in the
group concerning which is the better wire to use, solid or stranded.

So please enlighten me as to is solid, or stranded, better to use!

As with my mistakes with you, there are others out there evidently
proclaiming "truths" that are not "true"


In your opinion, what size wire, and should it be solid or stranded, for
both amp to speaker connection, and also be used for internal connections?


Not to be flippant, but the right size. And that's dependent upon the
application

A home system running at about 70w RMS into 4 ohm speakers. The speaker
wire lenghts being about 15' from amp to box. I had always thought that
using 16g lamp cord was suffient considering the amp was putting out
less than 120v


Alas, what I was "informed" to "inform" those I sold systems to. Notice
how informed is quoted so as to point out it is not my assumption, but
what I was told was true. As you have pointed out, the resistance
difference is negligible.


Aha! the beginnings of an actual questioning of an assumption!

That's what you have been baiting me on to understand, thank you. It
causes one to have a better understanding of the answer other than just
giving the answer and me memorizing a new answer.

A great teaching method !!

Kms = Ksurr + Kspid

And I am to understand then the the Ksurr and the Kspid are not
interchangable in their order in the equation?

Not being a jerk, what am I missing between the formula and your
hypothesis of the spider having more "weight" in the equation?


Consider the following:

c = a + b

If a is larger than b,

And matmaticaly the "a" will always start out larger than the "b"
due to the begining data value ratios being used?

setting A to 0 will result in a greater change
in c than setting b to zero. For example:

c = 4 + 1

of, of course 5. If I change the 1 to a 0:

c = 4 + 0

the result is 4, a 20% reduction in the result. But if I change
the 4 to a 0:

c = 0 + 1

the result is 1, an 80% change in the resulting value. Thus, in
such a relation, the larger value clearly carries more "weight."

Then my assumtion of "c = a + b" is not the same as "c = b + a", though
algebraicaly it is the same before values are substituted for "a" & "b"

The "c = 4 + 1" is the begining point for the manipulation of data vs
both the "a" and "b" being arbitrary swapable variable numbers? The
begining numbers are a ratio to start with then?

It has been a while since I have had to use this type of math,
like 25 years, forgive me - lol

Now, had I included the current default designs currently coming out
of the majority of Far East manufacturers, we'd find that, in fact,
the ration was significanrtly higher, on the order of 5 or 6 to one.

With the 5 or 6 replacing the 4 in the equation?

Is this measurement of the 3-4 times on a new spider vs a spider that
has been "broken in" and has lost some stiffness?


Yes. Generally, MOST of that "break-in" change is self-recovering,
i.e.,
Measure the driver resonance, break it in, it's lower, for sure, but
then lety it sit for a few minutes, and it's almost back up to where
it
was to begin with.

Then the "breaking in" would not be the equivolent, as shall we say a
leather hinge that the more it is flexed, the easier it is to flex again
later?


Would it even matter
in the resonant freq. when constructing a box if the spider is given a
"work out" before being installed?


Depends upon the type of enclosure and the system design. In the case
of true acoustic suspension designs,

By this, do you mean a sealed box and not ported?

the cabinet is designed such that
the effective acoustic stiffness is at a minimum 3-4 times that of the
mechanical stiffness of the driver. Thus, since the enclosure
stiffness
dominates, changes in the driver stiffness (including unit-to-unit
variations, which are ineveitable) are relatively unimportant. In a
criticially tuned relfex system, it's more significant, because
generally
the enclosure stiffness and drievr stiffness are more proximal to one
another.


Or was this just sales hype I was
told as truth?


There may be some truth in it, but that truth got buried, it seems,
in the hype.

Such as is it the color "purple' or a mixture of "red and blue"?


What of the speakers in the 70's, which is where most of my "knowledge"
came from? Why were speakers like AR and Advent not ported back then?
Were their spiders not built as today's speaker's spiders? What am I
missing here?


You're missing the bigger pictu the correct notion that the
enclosure
and driver must work and be designed together as a system. Within the
limited realm of their expertise back then, that's precisely what AR
did: Vilchur knew, more on intuition then physics originally, that by
letting the ACOUSTIC stiffness by the dominating stiffness in the
system,
several hard to solve problems simply went away: linearity of the
suspension, unit-to-unit variations, and so on. The driver
manufacturing
technology of the time didn't allow for the tighter production
tolerances
necessary for properly desigtned reflexes, but that manufacturing
technology has advanced by leaps and bounds in the 45 years since AR
started their thing.

And my assumtions came from the speaker designs from back then. Speaker
design has change drasticaly since I first studied speakers.


The vertical movement of the spider should be as "loose as a goose" and
offer no resistance to the voice coil's desire to move.

That may be your assumption, but, alas, the data suggests quite the
contrary. 25 years ago I heald the same opinion, until the data showed
how wrong that opinion was.

Dating my knowledge would be back to the 70's as my starting point also.

These assumptions came from the fact that a speaker is a motor and the
spider was the "bearings" of the motor and the less resistance in the
bearings, the better the motor would perform.


And here's where the temrinology is faling you. "Resistance" has one
implicit connotation, while "stiffness" is something else.

Yes, I was assuming stiffness as the same as voice coil movment
restriction from the spider, not to be confused with ohmage resistance.

There are three quantities of relevance he resistance, stiffness
and mass. Two of these, stiffness and mass, are energy STORAGE
mechanisms: you start a mass moving, you give it a (kinetic) energy
equal to its mass times the velocity squared. You push on a stiffness
and hold it, you give it a (potential) energy equal to it's spring
constant times the distance squared (see the VERY interesting
similarity:

E = 1/2 mv^2

E = 1/2 kx^2

This energy you can get back again: try to slow the mass down, it
generates a force, let go of the spring, it bounces back. Both can
return the energy you put into them.

However, with the RESISTANCE, this is friction: put energy into a
resistance and it turns into heat. You can't turn the heat back into
usable motion: it's lost, never to come back in any useful form.

The resistance you feel when slowly pushing the cone is simply the
REACTIVE nature of the surround and spider pushing back. Let go,
and nearly all the enrgy you put into pushing it pushes the cone
back to where it started. That part that ISN'T returned causes the
suspension to heat up ever so slightly (and, interestingly enough,
makes the suspension a little looser: you have "broken it in." But
let it cool down and ...).

Now, INTUITIVELY, it seems like the stiffer the suspension, the less
efficient the speaker. But, sorry, intuition is wrong. This is because
the speaker does NOT work well at the sorts of speeds that you're
pushing at, it works at MUCH higher speeds. Push the cone in with your
hand as fats as you can. What sort of speed do you think you just
achieved? Maybe the equivalent of 1-2 inches per second. A speaker
moving back and forth 1/2" at a relatively low frequency of 20 Hz is
moving at a peak velocity of 63 inches per second, MUCH faster than
you could push it with your finger.

So the speaker cone mass and spider reluctance to move add together to
become kinetic energy and is passed back and forth (in/out) similar to
the ball toys on some peoples desk

Secondly, you have only pushed the speaker one way. In operation
the speaker is really moving back and forth, accelerating one way,
then accelerating the other, back and forth. NOW, it's not the
STIFFNESS that's important, IT'S THE MASS OF THE CONE. Thus, when we
analyze the situation and develop a mathematical expression for
efficiency, we find there is NOTHING in that expression for the
suspension stiffness AT ALL: a dominant term is driver mass.

Does not the spider stiffness get added to the driver mass of the cone
for the kinetic energy being transfered as the speaker mover in/out?


No dustcap constitutes a REAL BIG "leak" in the system.

By no dustcap, I am assuming you mean a dustcap missing completly vs a
difference in the type/style of dustcap?

By this, I am asssuming the rest of the enclosure would become affected
if the dust cap let air flow through it, vs the vented coil which is
just venting back inside to the enclosure and would not affect the total
internal volume in relation to port size. The vented voice coil is a
closed system then inside the enclosure?

The compression effect is important, but not in terms of the direct
influence on driver stiffness, but more on secondary effects, such as
non-linearities and noises.


Under low to medium power, I doubt that the first or third statement
would even matter and was more sales hype we were told, more than
distortion actually being audible or a change in linear response then?


It's certainly measurable in extreme cases: it might be audible.

And when you say might, I consider that meaning negligable except in
extreme measurment environments.

Remember that much of this work was done for sound-reinforcement
purposes,

Which is where my knowledge of speakers was used for first and then
transfered over to home systems.

where the amounts of power being dissipated are HUGE.
Consider, for example, that atypical direct-radiator speaker
has an efficiency of maybe 1% or so. That means that every 100 watts
you put into the speaker, only 1 watt is converted to sound. Where
to you think the other 99 watts go?

HEAT!

This would also be where some voice coils became liquid cooled?

And some of the speaker are driven with 1000 watts. Anything you can
do to get rid of that heat is going to make the life of the sound
guy much easier. You do NOT want to be crawling up a scaffolding to
replace a 15 inch woofer that burned out in the middle of a Metallica
concert.

I would perfer not to even have to change it after a concert also.
Fried speakes are some of the mosr disgusting smells around.


I was merely challenging, on a technical basis, the technical validity of your
assertion regarding the suitability of driver compliance to reflex
implementations.

I can't give a technical reason to you and I wish I could have a formula
to quote to back up what my ears heard. The ported, rolled suspension,
speakers (mid 70's) just did not have the "snap" on acoustic bass, or
drums, that the sealed ones did. The ported JBL and EV speakers did
have the "snap" and were rigid surrounds.

The only advantage that I "knew" at the time was the lower freq.
response in a smaller box size, when a speaker was ported.

I have no theories for preference. None are needed. People like
what they hear

Sort of like Dynaudio specing out flatter than the Seas, but the Seas
sounding warmer and more life like?


Also, what is your opinion of "compound loaded" speakers being used for
subs. The hype was that you could go just as low with 1/2 the box size.


and they are even MORE dependent upon variations in critical
parameters
such as compliance.

I take it this will be a whole new can of worms to be opened later to
discuss with you at another time after I understand what you are trying
to get through my limited understanding of the subject of sound
reproduction.

Ain't learnin' fun?

No, it isn't fun at all you turkey!!! (meant as a joke)

It is very frustrating for me. But true knowledge does not come easily.

But when I understand both the theories and the practical use of the
theory, it is better than fun. It has become workable knowledge then.

At present it is still very frustrating to me. I have to unlearn things
that I learned many years ago that I thought were truths, which might of
been truths at that time.

Your method of making me explain why I have an assumption and having me
to try and prove why that assumtion of "truth" is valid is a great way
to learn. It works better than just memorizing a new set of rules to go
by as the new "truths". Understanding is better than memorization.

I love telling the grocery baggers "OK" when they ask me "paper or
plastic" just to see the look on their face. People have been so
conditioned to look for an either/or answer and don't know what to do
when you throw a variable into the equation they are not expecting.

At first I found your methods to seem to be aggressive and did not see
them as me being a begining student who is learning from a zen master.

I was expecting answers, not for you to cause me to question why I
thought my answers were the "truth".

That is how the miscommunication got started between us, and as before,
I am very sorry I mistook your teaching style as an egotistic know it all!!

Thanks for your knowledge you have tried to pass to me even if I only
understood a small part of the vastness you passed on to me!!

John

I never represented it as "my" theory, and I would appreciate it if no
one else did, either.

Sorry, I should of said your understanding and practical use of theory
instead of calling it your theory.

Because it was a convenient model. It really dates back to Benjamin
Franklin, who gave the two charges their names, and, inconveniently,
got it backwards.

As a matyter of clarification, I would suggest the dichotomy is more
between physicists and engineers/technicians.

That makes more sense about physics, considering how quantum mechanics
and Newtonian physics seem to disagree, but both are right.

An example being, is light a wave or consist of photons? Depends on
what you measure and look for.

The following was sniped because of length concerning the
religous/scientific "expert" validty thing for those new to this post - JS

Well, that's directly contradicted precisely by the example of
Galileo, who was clearly a scientific expert. His theories were
based on observation, while those of the dominant power structure
were based on dogma. Because of the rigidity of that dogma,

He faced possible torture and almost lost his head as I recall from
history because the pope did not like his refusal to stop his teachings.

If I understand this correctly, you are saying that the size of the wire
from the amp to the speaker and the from the terminal to the woofer
doesn't matter.

I never said it was, did I. I asked the question as to why you think
it should be one way or the other.

I will attempt to answer the question the best I can from previous info
in this thread.

Smaller wire would offer a higher resistance from the speaker box
terminal to the woofer, thus a loss in power from the amp to the woofer.

The assumption then being, that the wire size to the speaker box should
be the same size wire going to the woofer.

As I understand from your explinations of resistence differences between
wire sizes, the length of wire from the terminal to the woofer is so
short, the added resistance would be negligable for power loss
calculations and wire size differences was more of a sales hype than
reality based?

I know that solid wire has less inductance than stranded so the highs
should be transferred better.


No, actually, taht's not true, not in ANY significant fashion.

Sorry, but I got that assumption from another thread going on in the
group concerning which is the better wire to use, solid or stranded.

So please enlighten me as to is solid, or stranded, better to use!

As with my mistakes with you, there are others out there evidently
proclaiming "truths" that are not "true"


In your opinion, what size wire, and should it be solid or stranded, for
both amp to speaker connection, and also be used for internal connections?


Not to be flippant, but the right size. And that's dependent upon the
application

A home system running at about 70w RMS into 4 ohm speakers. The speaker
wire lenghts being about 15' from amp to box. I had always thought that
using 16g lamp cord was suffient considering the amp was putting out
less than 120v


Alas, what I was "informed" to "inform" those I sold systems to. Notice
how informed is quoted so as to point out it is not my assumption, but
what I was told was true. As you have pointed out, the resistance
difference is negligible.


Aha! the beginnings of an actual questioning of an assumption!

That's what you have been baiting me on to understand, thank you. It
causes one to have a better understanding of the answer other than just
giving the answer and me memorizing a new answer.

A great teaching method !!

Kms = Ksurr + Kspid

And I am to understand then the the Ksurr and the Kspid are not
interchangable in their order in the equation?

Not being a jerk, what am I missing between the formula and your
hypothesis of the spider having more "weight" in the equation?


Consider the following:

c = a + b

If a is larger than b,

And matmaticaly the "a" will always start out larger than the "b"
due to the begining data value ratios being used?

setting A to 0 will result in a greater change
in c than setting b to zero. For example:

c = 4 + 1

of, of course 5. If I change the 1 to a 0:

c = 4 + 0

the result is 4, a 20% reduction in the result. But if I change
the 4 to a 0:

c = 0 + 1

the result is 1, an 80% change in the resulting value. Thus, in
such a relation, the larger value clearly carries more "weight."

Then my assumtion of "c = a + b" is not the same as "c = b + a", though
algebraicaly it is the same before values are substituted for "a" & "b"

The "c = 4 + 1" is the begining point for the manipulation of data vs
both the "a" and "b" being arbitrary swapable variable numbers? The
begining numbers are a ratio to start with then?

It has been a while since I have had to use this type of math,
like 25 years, forgive me - lol

Now, had I included the current default designs currently coming out
of the majority of Far East manufacturers, we'd find that, in fact,
the ration was significanrtly higher, on the order of 5 or 6 to one.

With the 5 or 6 replacing the 4 in the equation?

Is this measurement of the 3-4 times on a new spider vs a spider that
has been "broken in" and has lost some stiffness?


Yes. Generally, MOST of that "break-in" change is self-recovering,
i.e.,
Measure the driver resonance, break it in, it's lower, for sure, but
then lety it sit for a few minutes, and it's almost back up to where
it
was to begin with.

Then the "breaking in" would not be the equivolent, as shall we say a
leather hinge that the more it is flexed, the easier it is to flex again
later?


Would it even matter
in the resonant freq. when constructing a box if the spider is given a
"work out" before being installed?


Depends upon the type of enclosure and the system design. In the case
of true acoustic suspension designs,

By this, do you mean a sealed box and not ported?

the cabinet is designed such that
the effective acoustic stiffness is at a minimum 3-4 times that of the
mechanical stiffness of the driver. Thus, since the enclosure
stiffness
dominates, changes in the driver stiffness (including unit-to-unit
variations, which are ineveitable) are relatively unimportant. In a
criticially tuned relfex system, it's more significant, because
generally
the enclosure stiffness and drievr stiffness are more proximal to one
another.


Or was this just sales hype I was
told as truth?


There may be some truth in it, but that truth got buried, it seems,
in the hype.

Such as is it the color "purple' or a mixture of "red and blue"?


What of the speakers in the 70's, which is where most of my "knowledge"
came from? Why were speakers like AR and Advent not ported back then?
Were their spiders not built as today's speaker's spiders? What am I
missing here?


You're missing the bigger pictu the correct notion that the
enclosure
and driver must work and be designed together as a system. Within the
limited realm of their expertise back then, that's precisely what AR
did: Vilchur knew, more on intuition then physics originally, that by
letting the ACOUSTIC stiffness by the dominating stiffness in the
system,
several hard to solve problems simply went away: linearity of the
suspension, unit-to-unit variations, and so on. The driver
manufacturing
technology of the time didn't allow for the tighter production
tolerances
necessary for properly desigtned reflexes, but that manufacturing
technology has advanced by leaps and bounds in the 45 years since AR
started their thing.

And my assumtions came from the speaker designs from back then. Speaker
design has change drasticaly since I first studied speakers.


The vertical movement of the spider should be as "loose as a goose" and
offer no resistance to the voice coil's desire to move.

That may be your assumption, but, alas, the data suggests quite the
contrary. 25 years ago I heald the same opinion, until the data showed
how wrong that opinion was.

Dating my knowledge would be back to the 70's as my starting point also.

These assumptions came from the fact that a speaker is a motor and the
spider was the "bearings" of the motor and the less resistance in the
bearings, the better the motor would perform.


And here's where the temrinology is faling you. "Resistance" has one
implicit connotation, while "stiffness" is something else.

Yes, I was assuming stiffness as the same as voice coil movment
restriction from the spider, not to be confused with ohmage resistance.

There are three quantities of relevance he resistance, stiffness
and mass. Two of these, stiffness and mass, are energy STORAGE
mechanisms: you start a mass moving, you give it a (kinetic) energy
equal to its mass times the velocity squared. You push on a stiffness
and hold it, you give it a (potential) energy equal to it's spring
constant times the distance squared (see the VERY interesting
similarity:

E = 1/2 mv^2

E = 1/2 kx^2

This energy you can get back again: try to slow the mass down, it
generates a force, let go of the spring, it bounces back. Both can
return the energy you put into them.

However, with the RESISTANCE, this is friction: put energy into a
resistance and it turns into heat. You can't turn the heat back into
usable motion: it's lost, never to come back in any useful form.

The resistance you feel when slowly pushing the cone is simply the
REACTIVE nature of the surround and spider pushing back. Let go,
and nearly all the enrgy you put into pushing it pushes the cone
back to where it started. That part that ISN'T returned causes the
suspension to heat up ever so slightly (and, interestingly enough,
makes the suspension a little looser: you have "broken it in." But
let it cool down and ...).

Now, INTUITIVELY, it seems like the stiffer the suspension, the less
efficient the speaker. But, sorry, intuition is wrong. This is because
the speaker does NOT work well at the sorts of speeds that you're
pushing at, it works at MUCH higher speeds. Push the cone in with your
hand as fats as you can. What sort of speed do you think you just
achieved? Maybe the equivalent of 1-2 inches per second. A speaker
moving back and forth 1/2" at a relatively low frequency of 20 Hz is
moving at a peak velocity of 63 inches per second, MUCH faster than
you could push it with your finger.

So the speaker cone mass and spider reluctance to move add together to
become kinetic energy and is passed back and forth (in/out) similar to
the ball toys on some peoples desk

Secondly, you have only pushed the speaker one way. In operation
the speaker is really moving back and forth, accelerating one way,
then accelerating the other, back and forth. NOW, it's not the
STIFFNESS that's important, IT'S THE MASS OF THE CONE. Thus, when we
analyze the situation and develop a mathematical expression for
efficiency, we find there is NOTHING in that expression for the
suspension stiffness AT ALL: a dominant term is driver mass.

Does not the spider stiffness get added to the driver mass of the cone
for the kinetic energy being transfered as the speaker mover in/out?


No dustcap constitutes a REAL BIG "leak" in the system.

By no dustcap, I am assuming you mean a dustcap missing completly vs a
difference in the type/style of dustcap?

By this, I am asssuming the rest of the enclosure would become affected
if the dust cap let air flow through it, vs the vented coil which is
just venting back inside to the enclosure and would not affect the total
internal volume in relation to port size. The vented voice coil is a
closed system then inside the enclosure?

The compression effect is important, but not in terms of the direct
influence on driver stiffness, but more on secondary effects, such as
non-linearities and noises.


Under low to medium power, I doubt that the first or third statement
would even matter and was more sales hype we were told, more than
distortion actually being audible or a change in linear response then?


It's certainly measurable in extreme cases: it might be audible.

And when you say might, I consider that meaning negligable except in
extreme measurment environments.

Remember that much of this work was done for sound-reinforcement
purposes,

Which is where my knowledge of speakers was used for first and then
transfered over to home systems.

where the amounts of power being dissipated are HUGE.
Consider, for example, that atypical direct-radiator speaker
has an efficiency of maybe 1% or so. That means that every 100 watts
you put into the speaker, only 1 watt is converted to sound. Where
to you think the other 99 watts go?

HEAT!

This would also be where some voice coils became liquid cooled?

And some of the speaker are driven with 1000 watts. Anything you can
do to get rid of that heat is going to make the life of the sound
guy much easier. You do NOT want to be crawling up a scaffolding to
replace a 15 inch woofer that burned out in the middle of a Metallica
concert.

I would perfer not to even have to change it after a concert also.
Fried speakes are some of the mosr disgusting smells around.


I was merely challenging, on a technical basis, the technical validity of your
assertion regarding the suitability of driver compliance to reflex
implementations.

I can't give a technical reason to you and I wish I could have a formula
to quote to back up what my ears heard. The ported, rolled suspension,
speakers (mid 70's) just did not have the "snap" on acoustic bass, or
drums, that the sealed ones did. The ported JBL and EV speakers did
have the "snap" and were rigid surrounds.

The only advantage that I "knew" at the time was the lower freq.
response in a smaller box size, when a speaker was ported.

I have no theories for preference. None are needed. People like
what they hear

Sort of like Dynaudio specing out flatter than the Seas, but the Seas
sounding warmer and more life like?


Also, what is your opinion of "compound loaded" speakers being used for
subs. The hype was that you could go just as low with 1/2 the box size.


and they are even MORE dependent upon variations in critical
parameters
such as compliance.

I take it this will be a whole new can of worms to be opened later to
discuss with you at another time after I understand what you are trying
to get through my limited understanding of the subject of sound
reproduction.

Ain't learnin' fun?

No, it isn't fun at all you turkey!!! (meant as a joke)

It is very frustrating for me. But true knowledge does not come easily.

But when I understand both the theories and the practical use of the
theory, it is better than fun. It has become workable knowledge then.

At present it is still very frustrating to me. I have to unlearn things
that I learned many years ago that I thought were truths, which might of
been truths at that time.

Your method of making me explain why I have an assumption and having me
to try and prove why that assumtion of "truth" is valid is a great way
to learn. It works better than just memorizing a new set of rules to go
by as the new "truths". Understanding is better than memorization.

I love telling the grocery baggers "OK" when they ask me "paper or
plastic" just to see the look on their face. People have been so
conditioned to look for an either/or answer and don't know what to do
when you throw a variable into the equation they are not expecting.

At first I found your methods to seem to be aggressive and did not see
them as me being a begining student who is learning from a zen master.

I was expecting answers, not for you to cause me to question why I
thought my answers were the "truth".

That is how the miscommunication got started between us, and as before,
I am very sorry I mistook your teaching style as an egotistic know it all!!

Thanks for your knowledge you have tried to pass to me even if I only
understood a small part of the vastness you passed on to me!!

John

I never represented it as "my" theory, and I would appreciate it if no
one else did, either.

Sorry, I should of said your understanding and practical use of theory
instead of calling it your theory.

Because it was a convenient model. It really dates back to Benjamin
Franklin, who gave the two charges their names, and, inconveniently,
got it backwards.

As a matyter of clarification, I would suggest the dichotomy is more
between physicists and engineers/technicians.

That makes more sense about physics, considering how quantum mechanics
and Newtonian physics seem to disagree, but both are right.

An example being, is light a wave or consist of photons? Depends on
what you measure and look for.

The following was sniped because of length concerning the
religous/scientific "expert" validty thing for those new to this post - JS

Well, that's directly contradicted precisely by the example of
Galileo, who was clearly a scientific expert. His theories were
based on observation, while those of the dominant power structure
were based on dogma. Because of the rigidity of that dogma,

He faced possible torture and almost lost his head as I recall from
history because the pope did not like his refusal to stop his teachings.

If I understand this correctly, you are saying that the size of the wire
from the amp to the speaker and the from the terminal to the woofer
doesn't matter.

I never said it was, did I. I asked the question as to why you think
it should be one way or the other.

I will attempt to answer the question the best I can from previous info
in this thread.

Smaller wire would offer a higher resistance from the speaker box
terminal to the woofer, thus a loss in power from the amp to the woofer.

The assumption then being, that the wire size to the speaker box should
be the same size wire going to the woofer.

As I understand from your explinations of resistence differences between
wire sizes, the length of wire from the terminal to the woofer is so
short, the added resistance would be negligable for power loss
calculations and wire size differences was more of a sales hype than
reality based?

I know that solid wire has less inductance than stranded so the highs
should be transferred better.


No, actually, taht's not true, not in ANY significant fashion.

Sorry, but I got that assumption from another thread going on in the
group concerning which is the better wire to use, solid or stranded.

So please enlighten me as to is solid, or stranded, better to use!

As with my mistakes with you, there are others out there evidently
proclaiming "truths" that are not "true"


In your opinion, what size wire, and should it be solid or stranded, for
both amp to speaker connection, and also be used for internal connections?


Not to be flippant, but the right size. And that's dependent upon the
application

A home system running at about 70w RMS into 4 ohm speakers. The speaker
wire lenghts being about 15' from amp to box. I had always thought that
using 16g lamp cord was suffient considering the amp was putting out
less than 120v


Alas, what I was "informed" to "inform" those I sold systems to. Notice
how informed is quoted so as to point out it is not my assumption, but
what I was told was true. As you have pointed out, the resistance
difference is negligible.


Aha! the beginnings of an actual questioning of an assumption!

That's what you have been baiting me on to understand, thank you. It
causes one to have a better understanding of the answer other than just
giving the answer and me memorizing a new answer.

A great teaching method !!

Kms = Ksurr + Kspid

And I am to understand then the the Ksurr and the Kspid are not
interchangable in their order in the equation?

Not being a jerk, what am I missing between the formula and your
hypothesis of the spider having more "weight" in the equation?


Consider the following:

c = a + b

If a is larger than b,

And matmaticaly the "a" will always start out larger than the "b"
due to the begining data value ratios being used?

setting A to 0 will result in a greater change
in c than setting b to zero. For example:

c = 4 + 1

of, of course 5. If I change the 1 to a 0:

c = 4 + 0

the result is 4, a 20% reduction in the result. But if I change
the 4 to a 0:

c = 0 + 1

the result is 1, an 80% change in the resulting value. Thus, in
such a relation, the larger value clearly carries more "weight."

Then my assumtion of "c = a + b" is not the same as "c = b + a", though
algebraicaly it is the same before values are substituted for "a" & "b"

The "c = 4 + 1" is the begining point for the manipulation of data vs
both the "a" and "b" being arbitrary swapable variable numbers? The
begining numbers are a ratio to start with then?

It has been a while since I have had to use this type of math,
like 25 years, forgive me - lol

Now, had I included the current default designs currently coming out
of the majority of Far East manufacturers, we'd find that, in fact,
the ration was significanrtly higher, on the order of 5 or 6 to one.

With the 5 or 6 replacing the 4 in the equation?

Is this measurement of the 3-4 times on a new spider vs a spider that
has been "broken in" and has lost some stiffness?


Yes. Generally, MOST of that "break-in" change is self-recovering,
i.e.,
Measure the driver resonance, break it in, it's lower, for sure, but
then lety it sit for a few minutes, and it's almost back up to where
it
was to begin with.

Then the "breaking in" would not be the equivolent, as shall we say a
leather hinge that the more it is flexed, the easier it is to flex again
later?


Would it even matter
in the resonant freq. when constructing a box if the spider is given a
"work out" before being installed?


Depends upon the type of enclosure and the system design. In the case
of true acoustic suspension designs,

By this, do you mean a sealed box and not ported?

the cabinet is designed such that
the effective acoustic stiffness is at a minimum 3-4 times that of the
mechanical stiffness of the driver. Thus, since the enclosure
stiffness
dominates, changes in the driver stiffness (including unit-to-unit
variations, which are ineveitable) are relatively unimportant. In a
criticially tuned relfex system, it's more significant, because
generally
the enclosure stiffness and drievr stiffness are more proximal to one
another.


Or was this just sales hype I was
told as truth?


There may be some truth in it, but that truth got buried, it seems,
in the hype.

Such as is it the color "purple' or a mixture of "red and blue"?


What of the speakers in the 70's, which is where most of my "knowledge"
came from? Why were speakers like AR and Advent not ported back then?
Were their spiders not built as today's speaker's spiders? What am I
missing here?


You're missing the bigger pictu the correct notion that the
enclosure
and driver must work and be designed together as a system. Within the
limited realm of their expertise back then, that's precisely what AR
did: Vilchur knew, more on intuition then physics originally, that by
letting the ACOUSTIC stiffness by the dominating stiffness in the
system,
several hard to solve problems simply went away: linearity of the
suspension, unit-to-unit variations, and so on. The driver
manufacturing
technology of the time didn't allow for the tighter production
tolerances
necessary for properly desigtned reflexes, but that manufacturing
technology has advanced by leaps and bounds in the 45 years since AR
started their thing.

And my assumtions came from the speaker designs from back then. Speaker
design has change drasticaly since I first studied speakers.


The vertical movement of the spider should be as "loose as a goose" and
offer no resistance to the voice coil's desire to move.

That may be your assumption, but, alas, the data suggests quite the
contrary. 25 years ago I heald the same opinion, until the data showed
how wrong that opinion was.

Dating my knowledge would be back to the 70's as my starting point also.

These assumptions came from the fact that a speaker is a motor and the
spider was the "bearings" of the motor and the less resistance in the
bearings, the better the motor would perform.


And here's where the temrinology is faling you. "Resistance" has one
implicit connotation, while "stiffness" is something else.

Yes, I was assuming stiffness as the same as voice coil movment
restriction from the spider, not to be confused with ohmage resistance.

There are three quantities of relevance he resistance, stiffness
and mass. Two of these, stiffness and mass, are energy STORAGE
mechanisms: you start a mass moving, you give it a (kinetic) energy
equal to its mass times the velocity squared. You push on a stiffness
and hold it, you give it a (potential) energy equal to it's spring
constant times the distance squared (see the VERY interesting
similarity:

E = 1/2 mv^2

E = 1/2 kx^2

This energy you can get back again: try to slow the mass down, it
generates a force, let go of the spring, it bounces back. Both can
return the energy you put into them.

However, with the RESISTANCE, this is friction: put energy into a
resistance and it turns into heat. You can't turn the heat back into
usable motion: it's lost, never to come back in any useful form.

The resistance you feel when slowly pushing the cone is simply the
REACTIVE nature of the surround and spider pushing back. Let go,
and nearly all the enrgy you put into pushing it pushes the cone
back to where it started. That part that ISN'T returned causes the
suspension to heat up ever so slightly (and, interestingly enough,
makes the suspension a little looser: you have "broken it in." But
let it cool down and ...).

Now, INTUITIVELY, it seems like the stiffer the suspension, the less
efficient the speaker. But, sorry, intuition is wrong. This is because
the speaker does NOT work well at the sorts of speeds that you're
pushing at, it works at MUCH higher speeds. Push the cone in with your
hand as fats as you can. What sort of speed do you think you just
achieved? Maybe the equivalent of 1-2 inches per second. A speaker
moving back and forth 1/2" at a relatively low frequency of 20 Hz is
moving at a peak velocity of 63 inches per second, MUCH faster than
you could push it with your finger.

So the speaker cone mass and spider reluctance to move add together to
become kinetic energy and is passed back and forth (in/out) similar to
the ball toys on some peoples desk

Secondly, you have only pushed the speaker one way. In operation
the speaker is really moving back and forth, accelerating one way,
then accelerating the other, back and forth. NOW, it's not the
STIFFNESS that's important, IT'S THE MASS OF THE CONE. Thus, when we
analyze the situation and develop a mathematical expression for
efficiency, we find there is NOTHING in that expression for the
suspension stiffness AT ALL: a dominant term is driver mass.

Does not the spider stiffness get added to the driver mass of the cone
for the kinetic energy being transfered as the speaker mover in/out?


No dustcap constitutes a REAL BIG "leak" in the system.

By no dustcap, I am assuming you mean a dustcap missing completly vs a
difference in the type/style of dustcap?

By this, I am asssuming the rest of the enclosure would become affected
if the dust cap let air flow through it, vs the vented coil which is
just venting back inside to the enclosure and would not affect the total
internal volume in relation to port size. The vented voice coil is a
closed system then inside the enclosure?

The compression effect is important, but not in terms of the direct
influence on driver stiffness, but more on secondary effects, such as
non-linearities and noises.


Under low to medium power, I doubt that the first or third statement
would even matter and was more sales hype we were told, more than
distortion actually being audible or a change in linear response then?


It's certainly measurable in extreme cases: it might be audible.

And when you say might, I consider that meaning negligable except in
extreme measurment environments.

Remember that much of this work was done for sound-reinforcement
purposes,

Which is where my knowledge of speakers was used for first and then
transfered over to home systems.

where the amounts of power being dissipated are HUGE.
Consider, for example, that atypical direct-radiator speaker
has an efficiency of maybe 1% or so. That means that every 100 watts
you put into the speaker, only 1 watt is converted to sound. Where
to you think the other 99 watts go?

HEAT!

This would also be where some voice coils became liquid cooled?

And some of the speaker are driven with 1000 watts. Anything you can
do to get rid of that heat is going to make the life of the sound
guy much easier. You do NOT want to be crawling up a scaffolding to
replace a 15 inch woofer that burned out in the middle of a Metallica
concert.

I would perfer not to even have to change it after a concert also.
Fried speakes are some of the mosr disgusting smells around.


I was merely challenging, on a technical basis, the technical validity of your
assertion regarding the suitability of driver compliance to reflex
implementations.

I can't give a technical reason to you and I wish I could have a formula
to quote to back up what my ears heard. The ported, rolled suspension,
speakers (mid 70's) just did not have the "snap" on acoustic bass, or
drums, that the sealed ones did. The ported JBL and EV speakers did
have the "snap" and were rigid surrounds.

The only advantage that I "knew" at the time was the lower freq.
response in a smaller box size, when a speaker was ported.

I have no theories for preference. None are needed. People like
what they hear

Sort of like Dynaudio specing out flatter than the Seas, but the Seas
sounding warmer and more life like?


Also, what is your opinion of "compound loaded" speakers being used for
subs. The hype was that you could go just as low with 1/2 the box size.


and they are even MORE dependent upon variations in critical
parameters
such as compliance.

I take it this will be a whole new can of worms to be opened later to
discuss with you at another time after I understand what you are trying
to get through my limited understanding of the subject of sound
reproduction.

Ain't learnin' fun?

No, it isn't fun at all you turkey!!! (meant as a joke)

It is very frustrating for me. But true knowledge does not come easily.

But when I understand both the theories and the practical use of the
theory, it is better than fun. It has become workable knowledge then.

At present it is still very frustrating to me. I have to unlearn things
that I learned many years ago that I thought were truths, which might of
been truths at that time.

Your method of making me explain why I have an assumption and having me
to try and prove why that assumtion of "truth" is valid is a great way
to learn. It works better than just memorizing a new set of rules to go
by as the new "truths". Understanding is better than memorization.

I love telling the grocery baggers "OK" when they ask me "paper or
plastic" just to see the look on their face. People have been so
conditioned to look for an either/or answer and don't know what to do
when you throw a variable into the equation they are not expecting.

At first I found your methods to seem to be aggressive and did not see
them as me being a begining student who is learning from a zen master.

I was expecting answers, not for you to cause me to question why I
thought my answers were the "truth".

That is how the miscommunication got started between us, and as before,
I am very sorry I mistook your teaching style as an egotistic know it all!!

Thanks for your knowledge you have tried to pass to me even if I only
understood a small part of the vastness you passed on to me!!

John

I never represented it as "my" theory, and I would appreciate it if no
one else did, either.

Sorry, I should of said your understanding and practical use of theory
instead of calling it your theory.

Because it was a convenient model. It really dates back to Benjamin
Franklin, who gave the two charges their names, and, inconveniently,
got it backwards.

As a matyter of clarification, I would suggest the dichotomy is more
between physicists and engineers/technicians.

That makes more sense about physics, considering how quantum mechanics
and Newtonian physics seem to disagree, but both are right.

An example being, is light a wave or consist of photons? Depends on
what you measure and look for.

The following was sniped because of length concerning the
religous/scientific "expert" validty thing for those new to this post - JS

Well, that's directly contradicted precisely by the example of
Galileo, who was clearly a scientific expert. His theories were
based on observation, while those of the dominant power structure
were based on dogma. Because of the rigidity of that dogma,

He faced possible torture and almost lost his head as I recall from
history because the pope did not like his refusal to stop his teachings.

If I understand this correctly, you are saying that the size of the wire
from the amp to the speaker and the from the terminal to the woofer
doesn't matter.

I never said it was, did I. I asked the question as to why you think
it should be one way or the other.

I will attempt to answer the question the best I can from previous info
in this thread.

Smaller wire would offer a higher resistance from the speaker box
terminal to the woofer, thus a loss in power from the amp to the woofer.

The assumption then being, that the wire size to the speaker box should
be the same size wire going to the woofer.

As I understand from your explinations of resistence differences between
wire sizes, the length of wire from the terminal to the woofer is so
short, the added resistance would be negligable for power loss
calculations and wire size differences was more of a sales hype than
reality based?

I know that solid wire has less inductance than stranded so the highs
should be transferred better.


No, actually, taht's not true, not in ANY significant fashion.

Sorry, but I got that assumption from another thread going on in the
group concerning which is the better wire to use, solid or stranded.

So please enlighten me as to is solid, or stranded, better to use!

As with my mistakes with you, there are others out there evidently
proclaiming "truths" that are not "true"


In your opinion, what size wire, and should it be solid or stranded, for
both amp to speaker connection, and also be used for internal connections?


Not to be flippant, but the right size. And that's dependent upon the
application

A home system running at about 70w RMS into 4 ohm speakers. The speaker
wire lenghts being about 15' from amp to box. I had always thought that
using 16g lamp cord was suffient considering the amp was putting out
less than 120v


Alas, what I was "informed" to "inform" those I sold systems to. Notice
how informed is quoted so as to point out it is not my assumption, but
what I was told was true. As you have pointed out, the resistance
difference is negligible.


Aha! the beginnings of an actual questioning of an assumption!

That's what you have been baiting me on to understand, thank you. It
causes one to have a better understanding of the answer other than just
giving the answer and me memorizing a new answer.

A great teaching method !!

Kms = Ksurr + Kspid

And I am to understand then the the Ksurr and the Kspid are not
interchangable in their order in the equation?

Not being a jerk, what am I missing between the formula and your
hypothesis of the spider having more "weight" in the equation?


Consider the following:

c = a + b

If a is larger than b,

And matmaticaly the "a" will always start out larger than the "b"
due to the begining data value ratios being used?

setting A to 0 will result in a greater change
in c than setting b to zero. For example:

c = 4 + 1

of, of course 5. If I change the 1 to a 0:

c = 4 + 0

the result is 4, a 20% reduction in the result. But if I change
the 4 to a 0:

c = 0 + 1

the result is 1, an 80% change in the resulting value. Thus, in
such a relation, the larger value clearly carries more "weight."

Then my assumtion of "c = a + b" is not the same as "c = b + a", though
algebraicaly it is the same before values are substituted for "a" & "b"

The "c = 4 + 1" is the begining point for the manipulation of data vs
both the "a" and "b" being arbitrary swapable variable numbers? The
begining numbers are a ratio to start with then?

It has been a while since I have had to use this type of math,
like 25 years, forgive me - lol

Now, had I included the current default designs currently coming out
of the majority of Far East manufacturers, we'd find that, in fact,
the ration was significanrtly higher, on the order of 5 or 6 to one.

With the 5 or 6 replacing the 4 in the equation?

Is this measurement of the 3-4 times on a new spider vs a spider that
has been "broken in" and has lost some stiffness?


Yes. Generally, MOST of that "break-in" change is self-recovering,
i.e.,
Measure the driver resonance, break it in, it's lower, for sure, but
then lety it sit for a few minutes, and it's almost back up to where
it
was to begin with.

Then the "breaking in" would not be the equivolent, as shall we say a
leather hinge that the more it is flexed, the easier it is to flex again
later?


Would it even matter
in the resonant freq. when constructing a box if the spider is given a
"work out" before being installed?


Depends upon the type of enclosure and the system design. In the case
of true acoustic suspension designs,

By this, do you mean a sealed box and not ported?

the cabinet is designed such that
the effective acoustic stiffness is at a minimum 3-4 times that of the
mechanical stiffness of the driver. Thus, since the enclosure
stiffness
dominates, changes in the driver stiffness (including unit-to-unit
variations, which are ineveitable) are relatively unimportant. In a
criticially tuned relfex system, it's more significant, because
generally
the enclosure stiffness and drievr stiffness are more proximal to one
another.


Or was this just sales hype I was
told as truth?


There may be some truth in it, but that truth got buried, it seems,
in the hype.

Such as is it the color "purple' or a mixture of "red and blue"?


What of the speakers in the 70's, which is where most of my "knowledge"
came from? Why were speakers like AR and Advent not ported back then?
Were their spiders not built as today's speaker's spiders? What am I
missing here?


You're missing the bigger pictu the correct notion that the
enclosure
and driver must work and be designed together as a system. Within the
limited realm of their expertise back then, that's precisely what AR
did: Vilchur knew, more on intuition then physics originally, that by
letting the ACOUSTIC stiffness by the dominating stiffness in the
system,
several hard to solve problems simply went away: linearity of the
suspension, unit-to-unit variations, and so on. The driver
manufacturing
technology of the time didn't allow for the tighter production
tolerances
necessary for properly desigtned reflexes, but that manufacturing
technology has advanced by leaps and bounds in the 45 years since AR
started their thing.

And my assumtions came from the speaker designs from back then. Speaker
design has change drasticaly since I first studied speakers.


The vertical movement of the spider should be as "loose as a goose" and
offer no resistance to the voice coil's desire to move.

That may be your assumption, but, alas, the data suggests quite the
contrary. 25 years ago I heald the same opinion, until the data showed
how wrong that opinion was.

Dating my knowledge would be back to the 70's as my starting point also.

These assumptions came from the fact that a speaker is a motor and the
spider was the "bearings" of the motor and the less resistance in the
bearings, the better the motor would perform.


And here's where the temrinology is faling you. "Resistance" has one
implicit connotation, while "stiffness" is something else.

Yes, I was assuming stiffness as the same as voice coil movment
restriction from the spider, not to be confused with ohmage resistance.

There are three quantities of relevance he resistance, stiffness
and mass. Two of these, stiffness and mass, are energy STORAGE
mechanisms: you start a mass moving, you give it a (kinetic) energy
equal to its mass times the velocity squared. You push on a stiffness
and hold it, you give it a (potential) energy equal to it's spring
constant times the distance squared (see the VERY interesting
similarity:

E = 1/2 mv^2

E = 1/2 kx^2

This energy you can get back again: try to slow the mass down, it
generates a force, let go of the spring, it bounces back. Both can
return the energy you put into them.

However, with the RESISTANCE, this is friction: put energy into a
resistance and it turns into heat. You can't turn the heat back into
usable motion: it's lost, never to come back in any useful form.

The resistance you feel when slowly pushing the cone is simply the
REACTIVE nature of the surround and spider pushing back. Let go,
and nearly all the enrgy you put into pushing it pushes the cone
back to where it started. That part that ISN'T returned causes the
suspension to heat up ever so slightly (and, interestingly enough,
makes the suspension a little looser: you have "broken it in." But
let it cool down and ...).

Now, INTUITIVELY, it seems like the stiffer the suspension, the less
efficient the speaker. But, sorry, intuition is wrong. This is because
the speaker does NOT work well at the sorts of speeds that you're
pushing at, it works at MUCH higher speeds. Push the cone in with your
hand as fats as you can. What sort of speed do you think you just
achieved? Maybe the equivalent of 1-2 inches per second. A speaker
moving back and forth 1/2" at a relatively low frequency of 20 Hz is
moving at a peak velocity of 63 inches per second, MUCH faster than
you could push it with your finger.

So the speaker cone mass and spider reluctance to move add together to
become kinetic energy and is passed back and forth (in/out) similar to
the ball toys on some peoples desk

Secondly, you have only pushed the speaker one way. In operation
the speaker is really moving back and forth, accelerating one way,
then accelerating the other, back and forth. NOW, it's not the
STIFFNESS that's important, IT'S THE MASS OF THE CONE. Thus, when we
analyze the situation and develop a mathematical expression for
efficiency, we find there is NOTHING in that expression for the
suspension stiffness AT ALL: a dominant term is driver mass.

Does not the spider stiffness get added to the driver mass of the cone
for the kinetic energy being transfered as the speaker mover in/out?


No dustcap constitutes a REAL BIG "leak" in the system.

By no dustcap, I am assuming you mean a dustcap missing completly vs a
difference in the type/style of dustcap?

By this, I am asssuming the rest of the enclosure would become affected
if the dust cap let air flow through it, vs the vented coil which is
just venting back inside to the enclosure and would not affect the total
internal volume in relation to port size. The vented voice coil is a
closed system then inside the enclosure?

The compression effect is important, but not in terms of the direct
influence on driver stiffness, but more on secondary effects, such as
non-linearities and noises.


Under low to medium power, I doubt that the first or third statement
would even matter and was more sales hype we were told, more than
distortion actually being audible or a change in linear response then?


It's certainly measurable in extreme cases: it might be audible.

And when you say might, I consider that meaning negligable except in
extreme measurment environments.

Remember that much of this work was done for sound-reinforcement
purposes,

Which is where my knowledge of speakers was used for first and then
transfered over to home systems.

where the amounts of power being dissipated are HUGE.
Consider, for example, that atypical direct-radiator speaker
has an efficiency of maybe 1% or so. That means that every 100 watts
you put into the speaker, only 1 watt is converted to sound. Where
to you think the other 99 watts go?

HEAT!

This would also be where some voice coils became liquid cooled?

And some of the speaker are driven with 1000 watts. Anything you can
do to get rid of that heat is going to make the life of the sound
guy much easier. You do NOT want to be crawling up a scaffolding to
replace a 15 inch woofer that burned out in the middle of a Metallica
concert.

I would perfer not to even have to change it after a concert also.
Fried speakes are some of the mosr disgusting smells around.


I was merely challenging, on a technical basis, the technical validity of your
assertion regarding the suitability of driver compliance to reflex
implementations.

I can't give a technical reason to you and I wish I could have a formula
to quote to back up what my ears heard. The ported, rolled suspension,
speakers (mid 70's) just did not have the "snap" on acoustic bass, or
drums, that the sealed ones did. The ported JBL and EV speakers did
have the "snap" and were rigid surrounds.

The only advantage that I "knew" at the time was the lower freq.
response in a smaller box size, when a speaker was ported.

I have no theories for preference. None are needed. People like
what they hear

Sort of like Dynaudio specing out flatter than the Seas, but the Seas
sounding warmer and more life like?


Also, what is your opinion of "compound loaded" speakers being used for
subs. The hype was that you could go just as low with 1/2 the box size.


and they are even MORE dependent upon variations in critical
parameters
such as compliance.

I take it this will be a whole new can of worms to be opened later to
discuss with you at another time after I understand what you are trying
to get through my limited understanding of the subject of sound
reproduction.

Ain't learnin' fun?

No, it isn't fun at all you turkey!!! (meant as a joke)

It is very frustrating for me. But true knowledge does not come easily.

But when I understand both the theories and the practical use of the
theory, it is better than fun. It has become workable knowledge then.

At present it is still very frustrating to me. I have to unlearn things
that I learned many years ago that I thought were truths, which might of
been truths at that time.

Your method of making me explain why I have an assumption and having me
to try and prove why that assumtion of "truth" is valid is a great way
to learn. It works better than just memorizing a new set of rules to go
by as the new "truths". Understanding is better than memorization.

I love telling the grocery baggers "OK" when they ask me "paper or
plastic" just to see the look on their face. People have been so
conditioned to look for an either/or answer and don't know what to do
when you throw a variable into the equation they are not expecting.

At first I found your methods to seem to be aggressive and did not see
them as me being a begining student who is learning from a zen master.

I was expecting answers, not for you to cause me to question why I
thought my answers were the "truth".

That is how the miscommunication got started between us, and as before,
I am very sorry I mistook your teaching style as an egotistic know it all!!

Thanks for your knowledge you have tried to pass to me even if I only
understood a small part of the vastness you passed on to me!!

John

"Sanders" wrote in message
...
Engineers and technicians will always see things from different viewpoints

Not IME.

IE: Do "electrons" move or do the "holes" move in electronics.

Neither.

Why have 12g wire to the box and use 16g from the speaker terminal to
the woofer?

The lengths are vastly different.

The speaker mfg saves $$$ by using 16g instead of 12g.

Very little $. per unit. I would be more worried about what else such a
manufacturer has compromised on.

I still disagree with you about the spider being stiff, as its purpose
is to keep the voice coil in the proper horizontal tolerances for
movement inside the magnetic field gap.
The vertical movement of the spider should be as "loose as a goose" and
offer no resistance to the voice coil's desire to move.

Can you name a speaker with such a spider?

This desire of no resistance for the voice coil movement is why better
woofers also have vented coils so the air pressure is taken out of the
equation, which I am sure you could quote how it affects the speaker
movement and I can't. JBL engineers must do it for a reason.

Vented gaps mainly aid in cooling the voice coil.

TonyP.

"Sanders" wrote in message
...
Engineers and technicians will always see things from different viewpoints

Not IME.

IE: Do "electrons" move or do the "holes" move in electronics.

Neither.

Why have 12g wire to the box and use 16g from the speaker terminal to
the woofer?

The lengths are vastly different.

The speaker mfg saves $$$ by using 16g instead of 12g.

Very little $. per unit. I would be more worried about what else such a
manufacturer has compromised on.

I still disagree with you about the spider being stiff, as its purpose
is to keep the voice coil in the proper horizontal tolerances for
movement inside the magnetic field gap.
The vertical movement of the spider should be as "loose as a goose" and
offer no resistance to the voice coil's desire to move.

Can you name a speaker with such a spider?

This desire of no resistance for the voice coil movement is why better
woofers also have vented coils so the air pressure is taken out of the
equation, which I am sure you could quote how it affects the speaker
movement and I can't. JBL engineers must do it for a reason.

Vented gaps mainly aid in cooling the voice coil.

TonyP.

"Sanders" wrote in message
...
Engineers and technicians will always see things from different viewpoints

Not IME.

IE: Do "electrons" move or do the "holes" move in electronics.

Neither.

Why have 12g wire to the box and use 16g from the speaker terminal to
the woofer?

The lengths are vastly different.

The speaker mfg saves $$$ by using 16g instead of 12g.

Very little $. per unit. I would be more worried about what else such a
manufacturer has compromised on.

I still disagree with you about the spider being stiff, as its purpose
is to keep the voice coil in the proper horizontal tolerances for
movement inside the magnetic field gap.
The vertical movement of the spider should be as "loose as a goose" and
offer no resistance to the voice coil's desire to move.

Can you name a speaker with such a spider?

This desire of no resistance for the voice coil movement is why better
woofers also have vented coils so the air pressure is taken out of the
equation, which I am sure you could quote how it affects the speaker
movement and I can't. JBL engineers must do it for a reason.

Vented gaps mainly aid in cooling the voice coil.

TonyP.

"TonyP" wrote in message
. net...

Sure is confusing with two TonyP's now :-)

TonyP.

"TonyP" wrote in message
. net...

Sure is confusing with two TonyP's now :-)

TonyP.

"TonyP" wrote in message
. net...

Sure is confusing with two TonyP's now :-)

TonyP.

TonyP

Please read the post that I said apoligies to Dick in it. The
discussion ended up in that thread of this post to a lot of these
questions and their possible answers from Dick

TonyP

Please read the post that I said apoligies to Dick in it. The
discussion ended up in that thread of this post to a lot of these
questions and their possible answers from Dick

TonyP

Please read the post that I said apoligies to Dick in it. The
discussion ended up in that thread of this post to a lot of these
questions and their possible answers from Dick

Dang you Dick,

Now you have me wondering if in a sealed box, if the air
compression/expansion counteracts the mass of the cone from reaching the
length of the throw it needs to reproduce the note sent to it from the
amp.

Could the "tighter" bass I heard actually been a higher note than the
amp sent to the speaker because the mass of the speaker had too much
resistance to get to the proper throw length in the right amount of time
to reproduce the note the amp sent to the speaker.

The sound was "tighter", but not accurate as far a frequency was
concerned. The sound was of a higher frequency.

See, it worked! You made me think!!!

Thanks,

John

Dang you Dick,

Now you have me wondering if in a sealed box, if the air
compression/expansion counteracts the mass of the cone from reaching the
length of the throw it needs to reproduce the note sent to it from the
amp.

Could the "tighter" bass I heard actually been a higher note than the
amp sent to the speaker because the mass of the speaker had too much
resistance to get to the proper throw length in the right amount of time
to reproduce the note the amp sent to the speaker.

The sound was "tighter", but not accurate as far a frequency was
concerned. The sound was of a higher frequency.

See, it worked! You made me think!!!

Thanks,

John

Dang you Dick,

Now you have me wondering if in a sealed box, if the air
compression/expansion counteracts the mass of the cone from reaching the
length of the throw it needs to reproduce the note sent to it from the
amp.

Could the "tighter" bass I heard actually been a higher note than the
amp sent to the speaker because the mass of the speaker had too much
resistance to get to the proper throw length in the right amount of time
to reproduce the note the amp sent to the speaker.

The sound was "tighter", but not accurate as far a frequency was
concerned. The sound was of a higher frequency.

See, it worked! You made me think!!!

Thanks,

John

Sanders wrote in message ...
Dang you Dick,

Now you have me wondering if in a sealed box, if the air
compression/expansion counteracts the mass of the cone from reaching the
length of the throw it needs to reproduce the note sent to it from the
amp.

Could the "tighter" bass I heard actually been a higher note than the
amp sent to the speaker because the mass of the speaker had too much
resistance to get to the proper throw length in the right amount of time
to reproduce the note the amp sent to the speaker.

Again, you use the word "resistance" ambiguously in this context.

Be that as it may, without knowing the precise situation, e.g., the
speaker, I can only make a general comment, but that would be that
the hypothesis you describe is VERY unlikely.

Combinations of mechanical stiffness, acoustical stiffness, loss
elements such as electrical resistance and mechanical friction and
moving masses, all by themselves, simply cannot generate frequencies
that weren't there to begin with. If a mechanical stiffness is
suffiently non-linear for example, sure, but that's a different story.

The increased system stiffness afforded by a PROPERLY designed
sealed acoustic suspension enclosure most assuredly will not
generate the effect you're thinking of, in fact, one of the
intents of acoustic suspension is to replace the original dominant
but non-linear mechanical stiffness of the surround with a greater
but more linear acoustical stiffness of the enclosure. Now, taking
a normal driver and putting it in a small box results in what might
be an unacceptably high resonant frequency, meaning it doesn't go
down as far in the bass, but in the traditional acoustic suspension
designs, that problem was solved by makig the cone fairly massive.
But making the cone fairly massive does two things: it's harder to
cotrol electromagnetically and thus requires a larger magnet
assembly and is less efficient. And if you want to fit this all in
a plausibly small enough speaker to fit on a "bookshelf," a la the
old AR-3, you get bitten by the efficiency-volume-bandwidth relation,
e.g. to get 40 Hz out of a 1.5 cubic foot box, you have a dreadfully
low efficiency of like 79 dB/watt or something like that.

In something like the AR-3, the effective total system stiffness is
VERY high, yet it COULD reproduce 40 Hz, if but a little underdamped,
and it did NOT "generate new frequencies," or did so less than many
other speakers of its era (1960). It's bass is a little woolly sounding
to some, not as "tight" as it need be, which illustrates the point that
sealed speakers ARE NOT INHERENTLY "tight," just as vented speakers are
NOT INHERENTLY "non-tight" as some would claim.


The sound was "tighter", but not accurate as far a frequency was
concerned. The sound was of a higher frequency.

See, it worked! You made me think!!!

Thanks,

John

Sanders wrote in message ...
Dang you Dick,

Now you have me wondering if in a sealed box, if the air
compression/expansion counteracts the mass of the cone from reaching the
length of the throw it needs to reproduce the note sent to it from the
amp.

Could the "tighter" bass I heard actually been a higher note than the
amp sent to the speaker because the mass of the speaker had too much
resistance to get to the proper throw length in the right amount of time
to reproduce the note the amp sent to the speaker.

Again, you use the word "resistance" ambiguously in this context.

Be that as it may, without knowing the precise situation, e.g., the
speaker, I can only make a general comment, but that would be that
the hypothesis you describe is VERY unlikely.

Combinations of mechanical stiffness, acoustical stiffness, loss
elements such as electrical resistance and mechanical friction and
moving masses, all by themselves, simply cannot generate frequencies
that weren't there to begin with. If a mechanical stiffness is
suffiently non-linear for example, sure, but that's a different story.

The increased system stiffness afforded by a PROPERLY designed
sealed acoustic suspension enclosure most assuredly will not
generate the effect you're thinking of, in fact, one of the
intents of acoustic suspension is to replace the original dominant
but non-linear mechanical stiffness of the surround with a greater
but more linear acoustical stiffness of the enclosure. Now, taking
a normal driver and putting it in a small box results in what might
be an unacceptably high resonant frequency, meaning it doesn't go
down as far in the bass, but in the traditional acoustic suspension
designs, that problem was solved by makig the cone fairly massive.
But making the cone fairly massive does two things: it's harder to
cotrol electromagnetically and thus requires a larger magnet
assembly and is less efficient. And if you want to fit this all in
a plausibly small enough speaker to fit on a "bookshelf," a la the
old AR-3, you get bitten by the efficiency-volume-bandwidth relation,
e.g. to get 40 Hz out of a 1.5 cubic foot box, you have a dreadfully
low efficiency of like 79 dB/watt or something like that.

In something like the AR-3, the effective total system stiffness is
VERY high, yet it COULD reproduce 40 Hz, if but a little underdamped,
and it did NOT "generate new frequencies," or did so less than many
other speakers of its era (1960). It's bass is a little woolly sounding
to some, not as "tight" as it need be, which illustrates the point that
sealed speakers ARE NOT INHERENTLY "tight," just as vented speakers are
NOT INHERENTLY "non-tight" as some would claim.


The sound was "tighter", but not accurate as far a frequency was
concerned. The sound was of a higher frequency.

See, it worked! You made me think!!!

Thanks,

John

Sanders wrote in message ...
Dang you Dick,

Now you have me wondering if in a sealed box, if the air
compression/expansion counteracts the mass of the cone from reaching the
length of the throw it needs to reproduce the note sent to it from the
amp.

Could the "tighter" bass I heard actually been a higher note than the
amp sent to the speaker because the mass of the speaker had too much
resistance to get to the proper throw length in the right amount of time
to reproduce the note the amp sent to the speaker.

Again, you use the word "resistance" ambiguously in this context.

Be that as it may, without knowing the precise situation, e.g., the
speaker, I can only make a general comment, but that would be that
the hypothesis you describe is VERY unlikely.

Combinations of mechanical stiffness, acoustical stiffness, loss
elements such as electrical resistance and mechanical friction and
moving masses, all by themselves, simply cannot generate frequencies
that weren't there to begin with. If a mechanical stiffness is
suffiently non-linear for example, sure, but that's a different story.

The increased system stiffness afforded by a PROPERLY designed
sealed acoustic suspension enclosure most assuredly will not
generate the effect you're thinking of, in fact, one of the
intents of acoustic suspension is to replace the original dominant
but non-linear mechanical stiffness of the surround with a greater
but more linear acoustical stiffness of the enclosure. Now, taking
a normal driver and putting it in a small box results in what might
be an unacceptably high resonant frequency, meaning it doesn't go
down as far in the bass, but in the traditional acoustic suspension
designs, that problem was solved by makig the cone fairly massive.
But making the cone fairly massive does two things: it's harder to
cotrol electromagnetically and thus requires a larger magnet
assembly and is less efficient. And if you want to fit this all in
a plausibly small enough speaker to fit on a "bookshelf," a la the
old AR-3, you get bitten by the efficiency-volume-bandwidth relation,
e.g. to get 40 Hz out of a 1.5 cubic foot box, you have a dreadfully
low efficiency of like 79 dB/watt or something like that.

In something like the AR-3, the effective total system stiffness is
VERY high, yet it COULD reproduce 40 Hz, if but a little underdamped,
and it did NOT "generate new frequencies," or did so less than many
other speakers of its era (1960). It's bass is a little woolly sounding
to some, not as "tight" as it need be, which illustrates the point that
sealed speakers ARE NOT INHERENTLY "tight," just as vented speakers are
NOT INHERENTLY "non-tight" as some would claim.


The sound was "tighter", but not accurate as far a frequency was
concerned. The sound was of a higher frequency.

See, it worked! You made me think!!!

Thanks,

John

Could the "tighter" bass I heard actually been a higher note than the
amp sent to the speaker because the mass of the speaker had too much
resistance to get to the proper throw length in the right amount of time
to reproduce the note the amp sent to the speaker.


Again, you use the word "resistance" ambiguously in this context.

Be that as it may, without knowing the precise situation, e.g., the
speaker, I can only make a general comment, but that would be that
the hypothesis you describe is VERY unlikely.

Combinations of mechanical stiffness, acoustical stiffness, loss
elements such as electrical resistance and mechanical friction and
moving masses, all by themselves, simply cannot generate frequencies
that weren't there to begin with. If a mechanical stiffness is
suffiently non-linear for example, sure, but that's a different story.

The increased system stiffness afforded by a PROPERLY designed
sealed acoustic suspension enclosure most assuredly will not
generate the effect you're thinking of, in fact, one of the
intents of acoustic suspension is to replace the original dominant
but non-linear mechanical stiffness of the surround with a greater
but more linear acoustical stiffness of the enclosure.

I actually understood what you just said - wow! My first small step of
undersanding with an infinite amount of steps of learning to go.


Now, taking
a normal driver and putting it in a small box results in what might
be an unacceptably high resonant frequency,

We did this intentionaly so as to get the speaker to have a better
efficency for being used as a stage monitor.

meaning it doesn't go
down as far in the bass, but in the traditional acoustic suspension
designs, that problem was solved by makig the cone fairly massive.
But making the cone fairly massive does two things: it's harder to
cotrol electromagnetically and thus requires a larger magnet
assembly and is less efficient. And if you want to fit this all in
a plausibly small enough speaker to fit on a "bookshelf," a la the
old AR-3, you get bitten by the efficiency-volume-bandwidth relation,
e.g. to get 40 Hz out of a 1.5 cubic foot box, you have a dreadfully
low efficiency of like 79 dB/watt or something like that.

Yes, the little Advents sounded great but took a good size amp to get
them moving. Very similar to the AR-3. I though the little Advents
sounded better than the large ones.

In something like the AR-3, the effective total system stiffness is
VERY high, yet it COULD reproduce 40 Hz, if but a little underdamped,
and it did NOT "generate new frequencies," or did so less than many
other speakers of its era (1960). It's bass is a little woolly sounding
to some, not as "tight" as it need be, which illustrates the point that
sealed speakers ARE NOT INHERENTLY "tight," just as vented speakers are
NOT INHERENTLY "non-tight" as some would claim.


It has been a while since I have constructed boxes and that is why all
of my "stupid sounding" questions. I know if I have the right data
before starting I can save $$$$ on the speaker system and spend it on
amps and a large screen tv instead. Please bear with my ignorance.

Thanks,

John

Could the "tighter" bass I heard actually been a higher note than the
amp sent to the speaker because the mass of the speaker had too much
resistance to get to the proper throw length in the right amount of time
to reproduce the note the amp sent to the speaker.


Again, you use the word "resistance" ambiguously in this context.

Be that as it may, without knowing the precise situation, e.g., the
speaker, I can only make a general comment, but that would be that
the hypothesis you describe is VERY unlikely.

Combinations of mechanical stiffness, acoustical stiffness, loss
elements such as electrical resistance and mechanical friction and
moving masses, all by themselves, simply cannot generate frequencies
that weren't there to begin with. If a mechanical stiffness is
suffiently non-linear for example, sure, but that's a different story.

The increased system stiffness afforded by a PROPERLY designed
sealed acoustic suspension enclosure most assuredly will not
generate the effect you're thinking of, in fact, one of the
intents of acoustic suspension is to replace the original dominant
but non-linear mechanical stiffness of the surround with a greater
but more linear acoustical stiffness of the enclosure.

I actually understood what you just said - wow! My first small step of
undersanding with an infinite amount of steps of learning to go.


Now, taking
a normal driver and putting it in a small box results in what might
be an unacceptably high resonant frequency,

We did this intentionaly so as to get the speaker to have a better
efficency for being used as a stage monitor.

meaning it doesn't go
down as far in the bass, but in the traditional acoustic suspension
designs, that problem was solved by makig the cone fairly massive.
But making the cone fairly massive does two things: it's harder to
cotrol electromagnetically and thus requires a larger magnet
assembly and is less efficient. And if you want to fit this all in
a plausibly small enough speaker to fit on a "bookshelf," a la the
old AR-3, you get bitten by the efficiency-volume-bandwidth relation,
e.g. to get 40 Hz out of a 1.5 cubic foot box, you have a dreadfully
low efficiency of like 79 dB/watt or something like that.

Yes, the little Advents sounded great but took a good size amp to get
them moving. Very similar to the AR-3. I though the little Advents
sounded better than the large ones.

In something like the AR-3, the effective total system stiffness is
VERY high, yet it COULD reproduce 40 Hz, if but a little underdamped,
and it did NOT "generate new frequencies," or did so less than many
other speakers of its era (1960). It's bass is a little woolly sounding
to some, not as "tight" as it need be, which illustrates the point that
sealed speakers ARE NOT INHERENTLY "tight," just as vented speakers are
NOT INHERENTLY "non-tight" as some would claim.


It has been a while since I have constructed boxes and that is why all
of my "stupid sounding" questions. I know if I have the right data
before starting I can save $$$$ on the speaker system and spend it on
amps and a large screen tv instead. Please bear with my ignorance.

Thanks,

John

Could the "tighter" bass I heard actually been a higher note than the
amp sent to the speaker because the mass of the speaker had too much
resistance to get to the proper throw length in the right amount of time
to reproduce the note the amp sent to the speaker.


Again, you use the word "resistance" ambiguously in this context.

Be that as it may, without knowing the precise situation, e.g., the
speaker, I can only make a general comment, but that would be that
the hypothesis you describe is VERY unlikely.

Combinations of mechanical stiffness, acoustical stiffness, loss
elements such as electrical resistance and mechanical friction and
moving masses, all by themselves, simply cannot generate frequencies
that weren't there to begin with. If a mechanical stiffness is
suffiently non-linear for example, sure, but that's a different story.

The increased system stiffness afforded by a PROPERLY designed
sealed acoustic suspension enclosure most assuredly will not
generate the effect you're thinking of, in fact, one of the
intents of acoustic suspension is to replace the original dominant
but non-linear mechanical stiffness of the surround with a greater
but more linear acoustical stiffness of the enclosure.

I actually understood what you just said - wow! My first small step of
undersanding with an infinite amount of steps of learning to go.


Now, taking
a normal driver and putting it in a small box results in what might
be an unacceptably high resonant frequency,

We did this intentionaly so as to get the speaker to have a better
efficency for being used as a stage monitor.

meaning it doesn't go
down as far in the bass, but in the traditional acoustic suspension
designs, that problem was solved by makig the cone fairly massive.
But making the cone fairly massive does two things: it's harder to
cotrol electromagnetically and thus requires a larger magnet
assembly and is less efficient. And if you want to fit this all in
a plausibly small enough speaker to fit on a "bookshelf," a la the
old AR-3, you get bitten by the efficiency-volume-bandwidth relation,
e.g. to get 40 Hz out of a 1.5 cubic foot box, you have a dreadfully
low efficiency of like 79 dB/watt or something like that.

Yes, the little Advents sounded great but took a good size amp to get
them moving. Very similar to the AR-3. I though the little Advents
sounded better than the large ones.

In something like the AR-3, the effective total system stiffness is
VERY high, yet it COULD reproduce 40 Hz, if but a little underdamped,
and it did NOT "generate new frequencies," or did so less than many
other speakers of its era (1960). It's bass is a little woolly sounding
to some, not as "tight" as it need be, which illustrates the point that
sealed speakers ARE NOT INHERENTLY "tight," just as vented speakers are
NOT INHERENTLY "non-tight" as some would claim.


It has been a while since I have constructed boxes and that is why all
of my "stupid sounding" questions. I know if I have the right data
before starting I can save $$$$ on the speaker system and spend it on
amps and a large screen tv instead. Please bear with my ignorance.

Thanks,

John

Sanders wrote in message ...
Now, taking
a normal driver and putting it in a small box results in what might
be an unacceptably high resonant frequency,

We did this intentionaly so as to get the speaker to have a better
efficency for being used as a stage monitor.

No, it won't. This is a common misinterpretation of the efficiency-
enclosure volume-bandwidth relationship. Stated simply, it is:

n0 = kn Vb F3^3

where n0 is the reference efficiency, kn is the system efficiency
constant, Vb is the enclosure volume and F3 is the low-frequency
3 dB cutoff frequency. Now, as it is written, it SEEMS to imply
that if you change the box size, you change the efficiency. But
that assumption is based on the fact that, for a given driver,
n0 is a dependent variable. It most assuredly is NOT.

The reference efficiency of a system is determined by the electro-
mechanical properties of the driver and, once designed and built,
that's pretty mush it. That efficiency is determined by properties
such as the mmoving mass of the cone, the electrical resistance of
the voice coil, the field density of the magnetic flux in the gap
and the amount of wire in that field. The reference efficiency is
not, and I repeat, IS NOT determined in any substantive way by ANY
of the stiffness parameters in the system, whether it's suspension
stiffness or enclosure stiffness.

If you take the same drivert and put it in three very different
sized boxes, you will find that the resulting systems WILL HAVE
THE SAME REFERENCE EFFICIENCY.

That, on an intuitive first glance, would seem to violate the
efficiency-volume-bandwidth relation:

n0 = kn Vb F3^3

but such a conclusion ASSUMES that the ONLY parameter we have
changed is Vb, and that's flat out wrong. Whether we wanted to
or not, when we changed the enclosure volume VB, we ALSO changed
both kn (which is determined by how the system is tuned) AND we
have also changed F3. All three of these variable will change
such that n0 remains pretty much the same.

Rearranging this relation illustrates the point. FOr example,
we could rearrange it as:

kn F3^3 = n0 / Vb

now, consider that n0 is an independent variable, indeed, for any
given driver, it's a constant, and that changing the box size MUST
change the product of F3^3 and kn: bascially what this is saying is
changing the box size for a given driver will change the system
response! Now, let's try another, mathematically valid rearrangement:

Vb = n0 / (kn F3^3)

Now, if you wanted to play games here, you could claim this says that
if you change the efficiency of the driver say, by putting a resistor
in series with it, the size of the enclosure would change! That's
clearly an absurd assertion on it's face, and illustrates rather
dramatically how the basic relation can be misinterpreted.

However, this rearrangement is not without value. If, for example,
you KNOW what the efficiency of your proposed system HAS to be, and
you KNOW what the system tuning and F3 frequency HAS to be, this
equation will tell you what the necessary enclosure size HAS to be
to get there, assuming you have a driver that will give you the
necessary properties.

The original form is equally useful: if you know the design goals
for enclosure size, system tuning and bandwidth, the relation will
tell you the maximum efficiency you can expect out of the system.
The relationship is, indeed, a beginning point in the system design
process: it sets the minimum set of basic parameters needed to
achieve the broadest of system constraints. It will tell you, for
example, that a driver that's MORE efficienct that what the equation
specifies WILL NOT WORK to achieve that system specification, something
will have to be sacrificed: either the system will have to be tuned
differently, the cutoff frequency has to be higher or the box has to
be larger, or some combination thereof.




meaning it doesn't go
down as far in the bass, but in the traditional acoustic suspension
designs, that problem was solved by makig the cone fairly massive.
But making the cone fairly massive does two things: it's harder to
cotrol electromagnetically and thus requires a larger magnet
assembly and is less efficient. And if you want to fit this all in
a plausibly small enough speaker to fit on a "bookshelf," a la the
old AR-3, you get bitten by the efficiency-volume-bandwidth relation,
e.g. to get 40 Hz out of a 1.5 cubic foot box, you have a dreadfully
low efficiency of like 79 dB/watt or something like that.

Yes, the little Advents sounded great but took a good size amp to get
them moving. Very similar to the AR-3. I though the little Advents
sounded better than the large ones.

In something like the AR-3, the effective total system stiffness is
VERY high, yet it COULD reproduce 40 Hz, if but a little underdamped,
and it did NOT "generate new frequencies," or did so less than many
other speakers of its era (1960). It's bass is a little woolly sounding
to some, not as "tight" as it need be, which illustrates the point that
sealed speakers ARE NOT INHERENTLY "tight," just as vented speakers are
NOT INHERENTLY "non-tight" as some would claim.


It has been a while since I have constructed boxes and that is why all
of my "stupid sounding" questions. I know if I have the right data
before starting I can save $$$$ on the speaker system and spend it on
amps and a large screen tv instead. Please bear with my ignorance.

Thanks,

John

Sanders wrote in message ...
Now, taking
a normal driver and putting it in a small box results in what might
be an unacceptably high resonant frequency,

We did this intentionaly so as to get the speaker to have a better
efficency for being used as a stage monitor.

No, it won't. This is a common misinterpretation of the efficiency-
enclosure volume-bandwidth relationship. Stated simply, it is:

n0 = kn Vb F3^3

where n0 is the reference efficiency, kn is the system efficiency
constant, Vb is the enclosure volume and F3 is the low-frequency
3 dB cutoff frequency. Now, as it is written, it SEEMS to imply
that if you change the box size, you change the efficiency. But
that assumption is based on the fact that, for a given driver,
n0 is a dependent variable. It most assuredly is NOT.

The reference efficiency of a system is determined by the electro-
mechanical properties of the driver and, once designed and built,
that's pretty mush it. That efficiency is determined by properties
such as the mmoving mass of the cone, the electrical resistance of
the voice coil, the field density of the magnetic flux in the gap
and the amount of wire in that field. The reference efficiency is
not, and I repeat, IS NOT determined in any substantive way by ANY
of the stiffness parameters in the system, whether it's suspension
stiffness or enclosure stiffness.

If you take the same drivert and put it in three very different
sized boxes, you will find that the resulting systems WILL HAVE
THE SAME REFERENCE EFFICIENCY.

That, on an intuitive first glance, would seem to violate the
efficiency-volume-bandwidth relation:

n0 = kn Vb F3^3

but such a conclusion ASSUMES that the ONLY parameter we have
changed is Vb, and that's flat out wrong. Whether we wanted to
or not, when we changed the enclosure volume VB, we ALSO changed
both kn (which is determined by how the system is tuned) AND we
have also changed F3. All three of these variable will change
such that n0 remains pretty much the same.

Rearranging this relation illustrates the point. FOr example,
we could rearrange it as:

kn F3^3 = n0 / Vb

now, consider that n0 is an independent variable, indeed, for any
given driver, it's a constant, and that changing the box size MUST
change the product of F3^3 and kn: bascially what this is saying is
changing the box size for a given driver will change the system
response! Now, let's try another, mathematically valid rearrangement:

Vb = n0 / (kn F3^3)

Now, if you wanted to play games here, you could claim this says that
if you change the efficiency of the driver say, by putting a resistor
in series with it, the size of the enclosure would change! That's
clearly an absurd assertion on it's face, and illustrates rather
dramatically how the basic relation can be misinterpreted.

However, this rearrangement is not without value. If, for example,
you KNOW what the efficiency of your proposed system HAS to be, and
you KNOW what the system tuning and F3 frequency HAS to be, this
equation will tell you what the necessary enclosure size HAS to be
to get there, assuming you have a driver that will give you the
necessary properties.

The original form is equally useful: if you know the design goals
for enclosure size, system tuning and bandwidth, the relation will
tell you the maximum efficiency you can expect out of the system.
The relationship is, indeed, a beginning point in the system design
process: it sets the minimum set of basic parameters needed to
achieve the broadest of system constraints. It will tell you, for
example, that a driver that's MORE efficienct that what the equation
specifies WILL NOT WORK to achieve that system specification, something
will have to be sacrificed: either the system will have to be tuned
differently, the cutoff frequency has to be higher or the box has to
be larger, or some combination thereof.




meaning it doesn't go
down as far in the bass, but in the traditional acoustic suspension
designs, that problem was solved by makig the cone fairly massive.
But making the cone fairly massive does two things: it's harder to
cotrol electromagnetically and thus requires a larger magnet
assembly and is less efficient. And if you want to fit this all in
a plausibly small enough speaker to fit on a "bookshelf," a la the
old AR-3, you get bitten by the efficiency-volume-bandwidth relation,
e.g. to get 40 Hz out of a 1.5 cubic foot box, you have a dreadfully
low efficiency of like 79 dB/watt or something like that.

Yes, the little Advents sounded great but took a good size amp to get
them moving. Very similar to the AR-3. I though the little Advents
sounded better than the large ones.

In something like the AR-3, the effective total system stiffness is
VERY high, yet it COULD reproduce 40 Hz, if but a little underdamped,
and it did NOT "generate new frequencies," or did so less than many
other speakers of its era (1960). It's bass is a little woolly sounding
to some, not as "tight" as it need be, which illustrates the point that
sealed speakers ARE NOT INHERENTLY "tight," just as vented speakers are
NOT INHERENTLY "non-tight" as some would claim.


It has been a while since I have constructed boxes and that is why all
of my "stupid sounding" questions. I know if I have the right data
before starting I can save $$$$ on the speaker system and spend it on
amps and a large screen tv instead. Please bear with my ignorance.

Thanks,

John

Sanders wrote in message ...
Now, taking
a normal driver and putting it in a small box results in what might
be an unacceptably high resonant frequency,

We did this intentionaly so as to get the speaker to have a better
efficency for being used as a stage monitor.

No, it won't. This is a common misinterpretation of the efficiency-
enclosure volume-bandwidth relationship. Stated simply, it is:

n0 = kn Vb F3^3

where n0 is the reference efficiency, kn is the system efficiency
constant, Vb is the enclosure volume and F3 is the low-frequency
3 dB cutoff frequency. Now, as it is written, it SEEMS to imply
that if you change the box size, you change the efficiency. But
that assumption is based on the fact that, for a given driver,
n0 is a dependent variable. It most assuredly is NOT.

The reference efficiency of a system is determined by the electro-
mechanical properties of the driver and, once designed and built,
that's pretty mush it. That efficiency is determined by properties
such as the mmoving mass of the cone, the electrical resistance of
the voice coil, the field density of the magnetic flux in the gap
and the amount of wire in that field. The reference efficiency is
not, and I repeat, IS NOT determined in any substantive way by ANY
of the stiffness parameters in the system, whether it's suspension
stiffness or enclosure stiffness.

If you take the same drivert and put it in three very different
sized boxes, you will find that the resulting systems WILL HAVE
THE SAME REFERENCE EFFICIENCY.

That, on an intuitive first glance, would seem to violate the
efficiency-volume-bandwidth relation:

n0 = kn Vb F3^3

but such a conclusion ASSUMES that the ONLY parameter we have
changed is Vb, and that's flat out wrong. Whether we wanted to
or not, when we changed the enclosure volume VB, we ALSO changed
both kn (which is determined by how the system is tuned) AND we
have also changed F3. All three of these variable will change
such that n0 remains pretty much the same.

Rearranging this relation illustrates the point. FOr example,
we could rearrange it as:

kn F3^3 = n0 / Vb

now, consider that n0 is an independent variable, indeed, for any
given driver, it's a constant, and that changing the box size MUST
change the product of F3^3 and kn: bascially what this is saying is
changing the box size for a given driver will change the system
response! Now, let's try another, mathematically valid rearrangement:

Vb = n0 / (kn F3^3)

Now, if you wanted to play games here, you could claim this says that
if you change the efficiency of the driver say, by putting a resistor
in series with it, the size of the enclosure would change! That's
clearly an absurd assertion on it's face, and illustrates rather
dramatically how the basic relation can be misinterpreted.

However, this rearrangement is not without value. If, for example,
you KNOW what the efficiency of your proposed system HAS to be, and
you KNOW what the system tuning and F3 frequency HAS to be, this
equation will tell you what the necessary enclosure size HAS to be
to get there, assuming you have a driver that will give you the
necessary properties.

The original form is equally useful: if you know the design goals
for enclosure size, system tuning and bandwidth, the relation will
tell you the maximum efficiency you can expect out of the system.
The relationship is, indeed, a beginning point in the system design
process: it sets the minimum set of basic parameters needed to
achieve the broadest of system constraints. It will tell you, for
example, that a driver that's MORE efficienct that what the equation
specifies WILL NOT WORK to achieve that system specification, something
will have to be sacrificed: either the system will have to be tuned
differently, the cutoff frequency has to be higher or the box has to
be larger, or some combination thereof.




meaning it doesn't go
down as far in the bass, but in the traditional acoustic suspension
designs, that problem was solved by makig the cone fairly massive.
But making the cone fairly massive does two things: it's harder to
cotrol electromagnetically and thus requires a larger magnet
assembly and is less efficient. And if you want to fit this all in
a plausibly small enough speaker to fit on a "bookshelf," a la the
old AR-3, you get bitten by the efficiency-volume-bandwidth relation,
e.g. to get 40 Hz out of a 1.5 cubic foot box, you have a dreadfully
low efficiency of like 79 dB/watt or something like that.

Yes, the little Advents sounded great but took a good size amp to get
them moving. Very similar to the AR-3. I though the little Advents
sounded better than the large ones.

In something like the AR-3, the effective total system stiffness is
VERY high, yet it COULD reproduce 40 Hz, if but a little underdamped,
and it did NOT "generate new frequencies," or did so less than many
other speakers of its era (1960). It's bass is a little woolly sounding
to some, not as "tight" as it need be, which illustrates the point that
sealed speakers ARE NOT INHERENTLY "tight," just as vented speakers are
NOT INHERENTLY "non-tight" as some would claim.


It has been a while since I have constructed boxes and that is why all
of my "stupid sounding" questions. I know if I have the right data
before starting I can save $$$$ on the speaker system and spend it on
amps and a large screen tv instead. Please bear with my ignorance.

Thanks,

John

(Dick Pierce) wrote in message . com...
Sanders wrote in message ...
Now, taking
a normal driver and putting it in a small box results in what might
be an unacceptably high resonant frequency,

We did this intentionaly so as to get the speaker to have a better
efficency for being used as a stage monitor.

No, it won't. This is a common misinterpretation of the efficiency-
enclosure volume-bandwidth relationship. Stated simply, it is:

n0 = kn Vb F3^3

Dick, would you care to share some general comments/insight regarding
the behavior of spkr(s) in an open-back enclosure, with respect to the
various basic formulae & behaviors you've mentioned for suspended or
loaded ones?

(Dick Pierce) wrote in message . com...
Sanders wrote in message ...
Now, taking
a normal driver and putting it in a small box results in what might
be an unacceptably high resonant frequency,

We did this intentionaly so as to get the speaker to have a better
efficency for being used as a stage monitor.

No, it won't. This is a common misinterpretation of the efficiency-
enclosure volume-bandwidth relationship. Stated simply, it is:

n0 = kn Vb F3^3

Dick, would you care to share some general comments/insight regarding
the behavior of spkr(s) in an open-back enclosure, with respect to the
various basic formulae & behaviors you've mentioned for suspended or
loaded ones?

(Dick Pierce) wrote in message . com...
Sanders wrote in message ...
Now, taking
a normal driver and putting it in a small box results in what might
be an unacceptably high resonant frequency,

We did this intentionaly so as to get the speaker to have a better
efficency for being used as a stage monitor.

No, it won't. This is a common misinterpretation of the efficiency-
enclosure volume-bandwidth relationship. Stated simply, it is:

n0 = kn Vb F3^3

Dick, would you care to share some general comments/insight regarding
the behavior of spkr(s) in an open-back enclosure, with respect to the
various basic formulae & behaviors you've mentioned for suspended or
loaded ones?

I'm still here Dick,

It is just taking me more time than I thought it would to digest the
info you gave me.



The original form is equally useful: if you know the design goals
for enclosure size, system tuning and bandwidth, the relation will
tell you the maximum efficiency you can expect out of the system.
The relationship is, indeed, a beginning point in the system design
process: it sets the minimum set of basic parameters needed to
achieve the broadest of system constraints. It will tell you, for
example, that a driver that's MORE efficienct that what the equation
specifies WILL NOT WORK to achieve that system specification, something
will have to be sacrificed: either the system will have to be tuned
differently, the cutoff frequency has to be higher or the box has to
be larger, or some combination thereof.


As I remember, the cutoff for the low end was higher, so it fits the
equation you gave. Did his design actually put out a higher SPL output
level per wattage in than if in the "right" size box that the speaker
was designed for.

Are speaker parameters (mass/spider/surround/etc) designed for
particular box sizes, or is this where the volume of the port comes into
play for different size boxes?

Also, does it matter if a port is round or rectangular? I have heard
both and if anyone could tell me the real truth, I figure it will be you.

Thanks,

John

I'm still here Dick,

It is just taking me more time than I thought it would to digest the
info you gave me.



The original form is equally useful: if you know the design goals
for enclosure size, system tuning and bandwidth, the relation will
tell you the maximum efficiency you can expect out of the system.
The relationship is, indeed, a beginning point in the system design
process: it sets the minimum set of basic parameters needed to
achieve the broadest of system constraints. It will tell you, for
example, that a driver that's MORE efficienct that what the equation
specifies WILL NOT WORK to achieve that system specification, something
will have to be sacrificed: either the system will have to be tuned
differently, the cutoff frequency has to be higher or the box has to
be larger, or some combination thereof.


As I remember, the cutoff for the low end was higher, so it fits the
equation you gave. Did his design actually put out a higher SPL output
level per wattage in than if in the "right" size box that the speaker
was designed for.

Are speaker parameters (mass/spider/surround/etc) designed for
particular box sizes, or is this where the volume of the port comes into
play for different size boxes?

Also, does it matter if a port is round or rectangular? I have heard
both and if anyone could tell me the real truth, I figure it will be you.

Thanks,

John