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  #81   Report Post  
Fat Bastard
 
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Default Subwoofer direction

I'll say it again, as I've said over and over. YOU, Tom Nousaine, keep
spouting that we are only offering "conjecture", and yet you have provided
nothing more yourself. You are conjecturing as much as the next guy. You
have posted no physical evidence of anything. You merely TYPE and expect
everyone to believe you. Why is your conjecture any better than the next
guys? We've already pointed out that we HAVE done tests in the past,
hundreds (maybe thousands) of times, and we've seen others do the same, and
it happens. Our word is the same as your word. NOBODY has provided any
physical evidence to support either side, yet you expect everyone to believe
your side merely because you are a relatively well known writer for a
popular mobile electronics rag.

But you and Eddie provide no data. It's just talk. Attempted verification

of
his 60-Hz point should be easy. I've done so twice in the past week.


Thosands? I see noevidence of that. But even so; it's not a popularity

contest.
It's either true pr it isn't. And its easy to verify with a simple

experiment.

I guess you don't read any of the major audio forums, or deal with people in
the real world of car audio every day then. I was in the business for 17+
years, and I heard this statement made at least once a week, quite often
more. I've seen it happen, be it just by ear/feel/whatever, as well as at
competitions where the only thing being played is subs, and only at 80hz and
below. I've watched guys test their systems, get a low #, and immediately
switch the box around (in their alloted time frame), and then hit it again
and achieve a higher #. If it isn't happening, then I'd like to know why the
mics and meters, and the people involved are seeing it happen.

So you're saying that a loud burp at 75 Hz doesn't have higher frequency
distortion and harmonic content?


No, I am not saying that, but if you have ever been involved in a dB Drag
event, you would know that they do not register anything above 100hz to
begin with. If your peak is above 100hz, you are disqualified. There is
filtering in place so that these frequencies are NOT a factor. Learn a
little about the subject before you try to debunk it.

But,no matter, we are talking here about whether 'aiming' your enclosure
generally increases low frequency output. It's easy to show with simple
experimentation that it doesn't.


So you're saying that controlled experimental conditions don't reveal the
truth. Great, tell that to scientists all over the world.


Yes, I'm saying quite often the results are bull****. How many times have
"scientists" told us that something was good for us, and six months later
they tell us that it is NOT good for us. Scientific evidence is often
disputed, and re-evaluated and found to be quite FALSE.

Why not supply some experimental data so we can replicate this? That's

what's
so funny about this whole deal.


As soon as I have the time, and energy to do it, I'll try to take care of
it. I'll even remember to provide real PROOF of what is happening, not just
mere conjecture like you keep providing. Anyone can SAY they did the tests
and that their results were as they suspected, but most people that do these
tests will actually take some photographs, and/or video tape to substantiate
their claims. Your "word" is not good enough for me if my word is not good
enough for you. lol

I've provided 2 sets of experimental data in the past week. You and Eddie

just
continue to argue. Get busy.


No, you've provided the same "conjecture" that you keep whining about.


You PROVE it. I haven't seen any documented evidence from you or Eddie.

Just
conjecture.


Same to you.



  #82   Report Post  
Nousaine
 
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Default Subwoofer direction

"Fat *******" wrote;

I'll say it again, as I've said over and over. YOU, Tom Nousaine, keep
spouting that we are only offering "conjecture", and yet you have provided
nothing more yourself. You are conjecturing as much as the next guy. You
have posted no physical evidence of anything. You merely TYPE and expect
everyone to believe you. Why is your conjecture any better than the next
guys?


Because mine can be replicated. You've not done even the first step.

We've already pointed out that we HAVE done tests in the past,
hundreds (maybe thousands) of times, and we've seen others do the same, and
it happens. Our word is the same as your word. NOBODY has provided any
physical evidence to support either side, yet you expect everyone to believe
your side merely because you are a relatively well known writer for a
popular mobile electronics rag.


No because I've provided a set of conditions that can be replicated for
verification. I've even duplicated the Eddie Cartoon exactly, measured and
posted the results. Do it yourself and document the results.


But you and Eddie provide no data. It's just talk. Attempted verification

of
his 60-Hz point should be easy. I've done so twice in the past week.


Thosands? I see noevidence of that. But even so; it's not a popularity

contest.
It's either true pr it isn't. And its easy to verify with a simple

experiment.

I guess you don't read any of the major audio forums, or deal with people in
the real world of car audio every day then. I was in the business for 17+
years, and I heard this statement made at least once a week, quite often
more.


And how many times by the same mistaken and/or uninformed people would you
estimate?

I've seen it happen, be it just by ear/feel/whatever, as well as at
competitions where the only thing being played is subs, and only at 80hz and
below. I've watched guys test their systems, get a low #, and immediately
switch the box around (in their alloted time frame), and then hit it again
and achieve a higher #. If it isn't happening, then I'd like to know why the
mics and meters, and the people involved are seeing it happen.

So you're saying that a loud burp at 75 Hz doesn't have higher frequency
distortion and harmonic content?


No, I am not saying that, but if you have ever been involved in a dB Drag
event, you would know that they do not register anything above 100hz to
begin with. If your peak is above 100hz, you are disqualified.


But the microphone doesn't know this and the SPL gathers in ALL the sound for
an SPL reading and it doesn't know whether harmonics are adding to the peak
reading or not.

There is
filtering in place so that these frequencies are NOT a factor. Learn a
little about the subject before you try to debunk it.


Same to you. I know a popular home subwoofer where after a certain level if you
put in 'more' 20 Hz a SLM will register a higher number but spectral analysis
shows that no more 20 Hz came out and that the extra SPL came from the 2nd
harmonic (40 Hz) which was greater than the fundamental. The microphone
generally has no way of knowing that.


But,no matter, we are talking here about whether 'aiming' your enclosure
generally increases low frequency output. It's easy to show with simple
experimentation that it doesn't.


So you're saying that controlled experimental conditions don't reveal the
truth. Great, tell that to scientists all over the world.


Yes, I'm saying quite often the results are bull****.


Sure some experimental data has been unable to be replicated. Just like the
Eddie cartoon. I replicated the experiment AND guess what the cancellation at
60 Hz doesn't happen. Try it yourself.

How many times have
"scientists" told us that something was good for us, and six months later
they tell us that it is NOT good for us. Scientific evidence is often
disputed, and re-evaluated and found to be quite FALSE.

Why not supply some experimental data so we can replicate this? That's

what's
so funny about this whole deal.


As soon as I have the time, and energy to do it, I'll try to take care of
it. I'll even remember to provide real PROOF of what is happening, not just
mere conjecture like you keep providing. Anyone can SAY they did the tests
and that their results were as they suspected, but most people that do these
tests will actually take some photographs, and/or video tape to substantiate
their claims. Your "word" is not good enough for me if my word is not good
enough for you. lol

I've provided 2 sets of experimental data in the past week. You and Eddie

just
continue to argue. Get busy.


No, you've provided the same "conjecture" that you keep whining about.


You PROVE it. I haven't seen any documented evidence from you or Eddie.

Just
conjecture.


Same to you.


Repeat; some experimental verification please.

  #83   Report Post  
Paul Vina
 
Posts: n/a
Default Subwoofer direction

It would be nice if I didn't have to drive 45 miles to my old shop to use
their meter, but it's cheaper than buying one!

Paul Vina


"Fat *******" wrote in message
...
Excellent. Thank you for the contradictory evidence to my (and the rest of
the majority of those responding so far) theory, and findings. See, I am

not
afraid to see a differing opinion, or results, even if it supports Tom and
his theory.

I hope you meter it to get some other information on it. Hopefully it will
spur others to do the same.

"Paul Vina" wrote in message
. net...
I just wanted to chime in on this one. In my wife's car she's running

an
S12L5. I have it crossed over at about 65Hz. I played a 60Hz tone at a
reasonable level and listened. Without making any adjustments, I opened

the
trunk, turned the box around and listened again and it sounded the same.
Then I moved the box to the rear of the trunk (again no volume changes)

and
listened and again it was the same. No matter where I put it or which
direction it faced it sounded the same. I'm not saying this was the

most
scientific test, but it satisfied my curiosity. I may get out an RTA

and
test it in a week or two and I'll post the results.

Paul Vina






  #87   Report Post  
Nousaine
 
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Default Subwoofer direction

"Paul Vina" wrote:

Where are you at?


Southeastern Michigan.

  #89   Report Post  
Paul Vina
 
Posts: n/a
Default Subwoofer direction

Oh well. I'm in N. CA

Paul Vina


"Nousaine" wrote in message
...
"Paul Vina" wrote:

Where are you at?


Southeastern Michigan.



  #90   Report Post  
Nousaine
 
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Default Subwoofer direction

Mike Sims
wrote:


says...

As I mentioned in another post. The effects at low frequencies in the car

by
"aiming" your woofer are due to higher frequency effects/artifacts being
reduced in amplitude. Often a good low pass filter or other tuning will

also
ameliorate these problems as well.

It is also true that most people are often pretty far off when they

'estimate'
frequency. When I play a 100 Hz sine wave and ask people what the frequency

is
they usually reply 50 or 60 Hz.


Being one that spent a lot of time around huge underground power
transformers, I have a pretty keen ear to the 60hz sound, and can
reproduce it on command.

However, you still lack any study's to demonstrate your theory which is:

"The effects at low frequencies in the car by "aiming" your woofer are
due to higher frequency effects/artifacts being reduced in amplitude."


While you may be right in this theory, you need to demonstrate it
scientifically, and answer the question which has been posed to you over
and over again on this list, which is ... *why* do these speakers sound
better when facing the rear of the car? OR *why* does it not matter?

Since higher frequencies are indeed directional, and audio fans know
this, your assertions sound (pardon the punn) logical. But we want to
see the science.


I've published a report on this topic in Car Stereo Review and I've posted
measurement data in this forum describing what happens.

But the 'idea' that subwoofers automatically sound 'better' facing the rear has
not been shown by anyone's science in this thread. It's just a popular notion.
I've described why this might be true in a given case.

But you're asking me for evidence that no one else has even bothered to make
even preliminary measurements on the topic.




  #92   Report Post  
Eric Desrochers
 
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Default Subwoofer direction

Nousaine wrote:

This argument is a red-herring. Yes it's true that a good sounding system will
have a gradually decreasing frequency response at about 3 dB per octave over
the spectrum at the listening position.


Sorry to step into this heated thread...

This 3 dB per octave will cause a 20 kHz sound to be 30 dB lower than a
20 Hz sound, is this what you are saying?

This could well be true but it's quite surprising at first glance!

--
Eric (Dero) Desrochers

Hiroshima 45, Tchernobyl 86, Windows 95
  #94   Report Post  
Nousaine
 
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(Eric Desrochers) wrote:




Nousaine wrote:

This argument is a red-herring. Yes it's true that a good sounding system

will
have a gradually decreasing frequency response at about 3 dB per octave

over
the spectrum at the listening position.


Sorry to step into this heated thread...

This 3 dB per octave will cause a 20 kHz sound to be 30 dB lower than a
20 Hz sound, is this what you are saying?

This could well be true but it's quite surprising at first glance!

--
Eric (Dero) Desrochers

Hiroshima 45, Tchernobyl 86, Windows 95


Many things seem to be surprising at first glance in audio. Like the silly idea
that aiming a subwoofer makes a difference at low frequencies.

There's a web-site and strong advocate that claims 'aming' a subwoofer has
large effects at low frequencies in a car. The reasoning is based on 'standing
wave' theory that appears logical on face but is patently wrong.

The proponent claims that a dual reflection surface (wall and floor) will
produce a standing wave pattern and a large null at 60 Hz if a woofer is placed
3 feet from a wall on the floor. According to the 'theory' a standing wave
cancellation is produced at 60 Hz and bass is compromised.

The idea is simply wrong. There can be a cancellation from a single boundary
cancellation but at 3-feet placement that has to occur at a frequency at least
2 or 3 times the source frequency. This is well know as the "Allison Effect".

Further a standing wave must have at least 2 opposing surfaces to form. In the
wrong example given above the effect cannot be a 'standing wave' because in
order for a standing wave to form we need two sound sources traveling in
opposite directions.
With the single boundary example the 'cancelling' wave (single boundary
reflection) is traveling in the same direction as the source. So it isn't a
standing wave and it doesn't occur at the fundamental frequency of the source.

But the basic idea seems logical with a cursory glance. Likewise it seems
strange that a proper listening position EQ might have a downward slope over
the spectrum when the measurement mic is in the listening position.

But that's how sounds occur in nature as well. A trumpet measured at the bell
and at a distant listeners ears will have the far-field slope as well.
  #95   Report Post  
Nousaine
 
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Default Subwoofer direction

(Eric Desrochers)
wrote:

Nousaine wrote:

Many things seem to be surprising at first glance in audio. Like the silly
idea that aiming a subwoofer makes a difference at low frequencies.


(snip)

I've read the whole thread. I have not tried to orient subs in any of
my cars yet (and it's not even an option in my current car) so I won't
comment on its benefits. You seem to be right on a scientific
standpoint but we know that several things in life exists that cannot be
explained by rational means so I won't take a position on this topic at
this time!


You don't need to take a position. If you'd like I'll send you a file that
shows the effects of facing a subwoofer in a car either to the front or rear
(and with the hatch open) both in terms of frequency response and max SPL over
the 10-62 Hz range.


But what happen to the old concept that bass is omnidirectionnal? Or
more exactly, frequencies whose wavelenght are over three time the
diameter of the reproducing driver are non directionnal?


They still hold true. The main difference is that in your home 80 Hz is 2
standard deviations below the frequency at which people can generally locate a
subwooer. In your car the people at Ford Audio found that 150 Hz (an octave up)
was the typical frequency where low frequencies began to become directional.
In a car a 100 Hz or lower crossover always seems to work perfectly and often
200 Hz can be made to work well with regard to direcionality. But recall plain
old frequency response above 100 Hz can become another issue to deal with.

But the basic idea seems logical with a cursory glance. Likewise it seems
strange that a proper listening position EQ might have a downward slope
over the spectrum when the measurement mic is in the listening position.

But that's how sounds occur in nature as well. A trumpet measured at the
bell and at a distant listeners ears will have the far-field slope as
well.


I understand and accept that. It's a well known fact that air absorb
higher frequencies more than lows pver a distance.


Directivity is an issue too.

But in a car, the
near field (which I'd usually describes as 1 meter from the source) is
often *farther* than the actual listening position.


No "near-field" has a specific meaning that in engineering terms means that the
microphone is within a half inch of the diaphram at low frequencies and sees
basically the anechoic response of the speaker.

It is true that the term "near-field" is generally used in way that more
correctly defines what is really the "direct field" of the speaker where the
sound falls off by 6 dB with every doubling of distance which is generally true
@ 1 meter in a room.

At the critical distance where the reflected sound is equal in intensity to the
direct sound we enter the far-field. In your car the radiating surfaces are so
close to the interior surfaces the listener is always in the far field. (the
amount of reflected sound is equal to or greater than direct sound.)

Why a car would
commend (or naturally produce?) a 3 dB per octave slope while a real
listening room (or show venue?) would have a 1.5 dB per octave?


Because there is no 'direct field' in the car and the space is much smaller. In
a similar way the acoustics of the living room differ from a concert hall.

But the effect on system tuning is that many people become irritated with the
equalization process because the try to make the system "flat" in the far field
without taking the slope into account and find it doesn't sound good.


Lots a questions! I'm part of various audio fields since 15 years but
wasn't made aware of this since yesterday!

-- Eric (Dero) Desrochers

Hiroshima 45, Tchernobyl 86, Windows 95


You can prove it to your self easily. Take a small loudspeaker and measure it
in the near-field (mic within a half inch of the cone); then meausre it in the
far field (say @ 4 meters) in a room and note the difference.

Put it in the car (on the dash if you can) and re-measure. Notice the shape of
the curve over the audio bandwidth.


  #96   Report Post  
Eric Desrochers
 
Posts: n/a
Default Subwoofer direction

Nousaine wrote:

But what happen to the old concept that bass is omnidirectionnal? Or
more exactly, frequencies whose wavelenght are over three time the
diameter of the reproducing driver are non directionnal?


They still hold true. The main difference is that in your home 80 Hz is 2
standard deviations below the frequency at which people can generally
locate a subwooer. In your car the people at Ford Audio found that 150 Hz
(an octave up) was the typical frequency where low frequencies began to
become directional.


So, a typical in-car driver reproducing frequencies below 80 Hz in a
linear fashion *is* omni-directional and humans cannot locate it either.

It would seem to render moot any sub "aiming" concept...

No "near-field" has a specific meaning that in engineering terms means
that the microphone is within a half inch of the diaphram at low
frequencies and sees basically the anechoic response of the speaker.


I stand corrected. I was under the impression that multi-way systems
(at least home speakers) were measured at 1 meter so to acount for the
inter-driver interaction.

At the critical distance where the reflected sound is equal in intensity
to the direct sound we enter the far-field. In your car the radiating
surfaces are so close to the interior surfaces the listener is always in
the far field. (the amount of reflected sound is equal to or greater than
direct sound.)


OK

Because there is no 'direct field' in the car and the space is much
smaller. In a similar way the acoustics of the living room differ from a
concert hall.

But the effect on system tuning is that many people become irritated with
the equalization process because the try to make the system "flat" in the
far field without taking the slope into account and find it doesn't sound
good.


Indeed. Any attemps to have 16 kHz at the mid range level proved to be
ear tearing!

But in a car using multiple drivers (ie sub in back, low-mid in doors
and tweeter on dash, how youd you approach frequency response measuring?
Adjust each driver individually to be flat in near-field or measure at
the listening position and try for the 3 dB per octave slope?

-- Eric (Dero) Desrochers

Hiroshima 45, Tchernobyl 86, Windows 95
  #97   Report Post  
Eddie Runner
 
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Eric Desrochers wrote:

So, a typical in-car driver reproducing frequencies below 80 Hz in a
linear fashion *is* omni-directional and humans cannot locate it either.

It would seem to render moot any sub "aiming" concept...


Its NOT the same thing!
Your talking about something completely different!

The OMNI Directional you seem to be talking about is really
called LOCALIZATION.... Which means a human cant localize
low frequencies... In other words, its easy for us to tell where
highs are coming from, but as sound gets really low the source
of the sound is hard for us to find just by listening... This means
that in a room (or car) you can place the woofer anywhere you
want to and you wont mess up the imaging...

From a localization point of view, the location of the woofer in
relation to the highs is unimportant because the bass doesnt appear
to come from one place, it appears to come from everywhere..

The reason is because the distance between our two ears is
much shorter than the wavelengths for this bass.

On the other hand,
this thread isnt talking about that at all.!!

Its not being able to tell where the woofer is with yrou ear, it is
the woofer playing louder into the listening area by positioning the
woofer at the optimal place in the car...

I wrote a paper on it
http://www.installer.com/tech/aiming.html

Every kid with a car stereo knows the bass is better when the box is turned
around backwards so the woofer itself is closer to the back of the car.

Tom on the other hand says it makes no difference in the amplitude of
the bass in the listening area and all these folks must be imagining it....


Eddie Runner

  #98   Report Post  
Eric Desrochers
 
Posts: n/a
Default Subwoofer direction

Eddie Runner wrote:



The OMNI Directional you seem to be talking about is really
called LOCALIZATION...


No. The imprecision of the human ear to discern low frequency is well
known, but in this case I was really talking about a sub driver being
omni-directionnal. Quote from the Loudspeaker Design Cookbook, by Vance
Dickason : "At frequencies where the wavelenght of sound is large
compared to the diameter of the cone, the radiation is spherical".

Go to any pro audio gear manufacturer and look at the polar plot or
specs of their subwoofers offering (by subwoofer I mean some cubic
enclosure containing a 18 inches driver meant to produce sub-low
frequencies).

A few examples :

http://www.meyersound.com/products/m...ifications.htm
http://www.apogee-sound.com/pdfs/aplSB-spec.pdf

Others, like JBL, Martin Audio, EV and EAW don't even bother with
posting directivity speacs because it's so well known they are omni.

Or do Google search with key words "bass sound directivity", "subwoofer
polar plot", low frequency directivity, etc.

--
Eric (Dero) Desrochers

Hiroshima 45, Tchernobyl 86, Windows 95
  #99   Report Post  
Eric Desrochers
 
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Eric Desrochers wrote:

No. The imprecision of the human ear to discern low frequency is well
known...


....should have been "to discern low frequency location", of course.

Sorry!

--
Eric (Dero) Desrochers

Hiroshima 45, Tchernobyl 86, Windows 95
  #100   Report Post  
Eddie Runner
 
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OK, good enough... Yes your right, the sound eminating
from the woofer does radiate out omnidirectionally...

It is very common for folks to use the omnidirectional wording
to describe our inability to localize low frequencies...

Now that were straight and in agreement on that point....

You said before that since its omnidirectionional the placement
of the woofer box is not a factor....

this is what made me thin you meant localization!
For localization the placement of the wooferbox isnt important

BUT, for placement in the vehicle for the least cancelation
the omnidirectional output of the wooferbox is EXACTLY
one of the factors that causes the problems I describe in my
paper..!!

Notice in my CARTOON drawings, when the woofer plays
there is a sound that goes into the vehicle and also a sound that
goes to the back of the vehicle ! This demonstrates the omni
output of the box...

So,
its precisely this multidirection output that allows the bad
reflections to happen!

I hope this is understandable...

Tom there shinks it DOESNT HAPPEN...
But most of us here know he is wrong...

Eddie Runner





Eric Desrochers wrote:

Eddie Runner wrote:



The OMNI Directional you seem to be talking about is really
called LOCALIZATION...


No. The imprecision of the human ear to discern low frequency is well
known, but in this case I was really talking about a sub driver being
omni-directionnal. Quote from the Loudspeaker Design Cookbook, by Vance
Dickason : "At frequencies where the wavelenght of sound is large
compared to the diameter of the cone, the radiation is spherical".




  #102   Report Post  
Eric Desrochers
 
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Eddie Runner wrote:

OK, good enough... Yes your right, the sound eminating
from the woofer does radiate out omnidirectionally...

It is very common for folks to use the omnidirectional wording
to describe our inability to localize low frequencies...

Now that were straight and in agreement on that point....

You said before that since its omnidirectionional the placement
of the woofer box is not a factor....


Hum, no. I have not talked about placement of the box, I have talked
about it's orientation, "aiming", which are two different things, of
course.

I do sound reinforcment as part of my day job and I'm into big home
theater here, so I know very well that the placement of a sub enclosure
will make or break a system. But this whole thread was about the
orientation of the sub (aiming, pointing).

So I submitted that a woofer is omni-directionnal, which you seem to
agree with, therefore you cannot "aim" an omnidirectional driver, which
is where we seem to diverge opinion.

A flashlight (tweeter) can be aimed because it's directional.
A bare light bulb (woofer) cannot because it's omnidirectional.

If so, how can having a woofer shooting into the rear hatch be any
better than shooting to the rear seat?

Having the box closer to the rear of the car however is different : you
are not only aiming it, you are *moving* it, which *may* change
something due to the (possible) better loading of the driver. Just like
puting a home sub near a wall or near a corner will reinforce it.

My 0.02$
--
Eric (Dero) Desrochers

Hiroshima 45, Tchernobyl 86, Windows 95
  #103   Report Post  
Soundfreak03
 
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o I submitted that a woofer is omni-directionnal, which you seem to
agree with, therefore you cannot "aim" an omnidirectional driver, which
is where we seem to diverge opinion.


If, as you contend, the subs are omni and they cannot be aimed then take your
pro sound subs and turn them around being careful that they stay on the same
plane. Do you think you will notice a difference in FOH? What about onstage?

A flashlight (tweeter) can be aimed because it's directional.
A bare light bulb (woofer) cannot because it's omnidirectional.


A woofer most certainly can be aimed.
Even a SUBwoofer can be aimed.

If so, how can having a woofer shooting into the rear hatch be any
better than shooting to the rear seat?


Look at Eddies cartoons, it is all there.


Les
  #104   Report Post  
Eddie Runner
 
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Eric Desrochers wrote:

Hum, no. I have not talked about placement of the box, I have talked
about it's orientation, "aiming", which are two different things, of
course.


well ok then, placement of the woofer, not the box...
If you aim a woofer *box* at you the woofer will be at point X
if you aim the woofer box away from you keeping the *box*
in the exact same place, the woofer will move to the other side of
the box, and the woofer will now no longer be at X, it will be
the width of the box further away from you....

So, aiming a woofer is usually achieved by turning the box, its
not actually the aiming of the woofer that makes the differences
we hear, but instead, its the position of the woofer changing relative
to the vehicle and our listening area in the vehicle...

And as pinted out in my cartoons, aiming the box IS moving
the woofer.... (TYPICLY)....

I do sound reinforcment as part of my day job and I'm into big home
theater here, so I know very well that the placement of a sub enclosure
will make or break a system. But this whole thread was about the
orientation of the sub (aiming, pointing).


Good enough, I guess it was stupid of me to assume you read my
paper and understood that although the paper is titled AIMING
it is really about POSITIONING the woofer....

Having the box closer to the rear of the car however is different : you
are not only aiming it, you are *moving* it, which *may* change
something due to the (possible) better loading of the driver. Just like
puting a home sub near a wall or near a corner will reinforce it.


it sounds like were on the same page, I think if you had taken 2 minutes
to read my article on this you would have been quick to agree ...

Eddie Runner
http://installer.com/tech/aiming.html

BTW, I titled the article AIMING because thats what the kiddos percieve
as the change, even though anyone that reads the article can easily see its
really position of the woofer itself that matters.... If I called the
article something
else, all the kids that turn the box around backwards in thier trunk and AIM

the woofer to the rear would probably never find my article....



  #105   Report Post  
Eric Desrochers
 
Posts: n/a
Default Subwoofer direction

Soundfreak03 wrote:

If, as you contend, the subs are omni and they cannot be aimed then take your
pro sound subs and turn them around being careful that they stay on the same
plane. Do you think you will notice a difference in FOH? What about onstage?


For a single 12 inches non-horn loaded playing below 80 Hz, I'll bet it
would not change a thing. Actually, if there is some wall behind the
speaker, you may notice an increased output.

However, a stack of 18 inches playing to, say, 120 Hz would be quite
different because the mutual coupling of multiple drivers would cause
some directivity in the higher bass.

Meyer went to great lenght to design a "cardioid" sub and the thing have
4 drivers, weight 400 lbs, need extensive on-board processing and huge
power to run. It's certainly not commonplace yet.

If you know of a single 12, 15 or 18 inches pro sub that have some
directivity below 80 Hz, please post references.

--
Eric (Dero) Desrochers

Hiroshima 45, Tchernobyl 86, Windows 95


  #106   Report Post  
Eric Desrochers
 
Posts: n/a
Default Subwoofer direction

Eddie Runner wrote:

well ok then, placement of the woofer, not the box...
If you aim a woofer *box* at you the woofer will be at point X
if you aim the woofer box away from you keeping the *box*
in the exact same place, the woofer will move to the other side of
the box, and the woofer will now no longer be at X, it will be
the width of the box further away from you....

So, aiming a woofer is usually achieved by turning the box, its
not actually the aiming of the woofer that makes the differences
we hear, but instead, its the position of the woofer changing relative
to the vehicle and our listening area in the vehicle...

And as pinted out in my cartoons, aiming the box IS moving
the woofer.... (TYPICLY)....


It would be in a small car, but say you have some mini-van. Turning the
box over would only marginally change the distance from you.

If you really meant "moving", you should have used that term. I guess
I'm overly nitpicking about the terms!

Good enough, I guess it was stupid of me to assume you read my
paper and understood that although the paper is titled AIMING
it is really about POSITIONING the woofer....


it sounds like were on the same page, I think if you had taken 2 minutes
to read my article on this you would have been quick to agree ...


I did read your page.

Eddie Runner
http://installer.com/tech/aiming.html

BTW, I titled the article AIMING because thats what the kiddos percieve
as the change, even though anyone that reads the article can easily see its
really position of the woofer itself that matters.... If I called the
article something
else, all the kids that turn the box around backwards in thier trunk and AIM

the woofer to the rear would probably never find my article....


I think that "placement of a sub enclosure in cars" is as catchy that
"aiming a sub..." but it's just me!

BTW, I browsed to your other papers too. Interesting stuff! Especially
the part about the tight bass! Often confused with frequency response
anomalies, like you pointed out, or the damping of the system. I always
laught when I hear about 8 inches being more tight than 12 inches!

Regards,
--
Eric (Dero) Desrochers

Hiroshima 45, Tchernobyl 86, Windows 95
  #107   Report Post  
Soundfreak03
 
Posts: n/a
Default Subwoofer direction

For a single 12 inches non-horn loaded playing below 80 Hz, I'll bet it
would not change a thing.


How much? Go to your venue and turn your subs around then. Or hell just walk
into the front of the sub then to the rear and you tell me if there is a
difference or not.

Actually, if there is some wall behind the
speaker, you may notice an increased output.


Perhaps, but you would most likely end up with some very odd delay times on the
subs.

However, a stack of 18 inches playing to, say, 120 Hz


You cross over 18s at 120?!?! Seems a little high for SUBwoofers. Let your
midbass speakers take care of that.

would be quite
different because the mutual coupling of multiple drivers would cause
some directivity in the higher bass


What does the multiple drivers have to do with it? But nonetheless you shouldnt
have higher bass in your subwoofers.

Meyer went to great lenght to design a "cardioid" sub and the thing have
4 drivers, weight 400 lbs, need extensive on-board processing and huge
power to run. It's certainly not commonplace yet.


Heard both of them, the PSW-6 and the M3D Sub. They are great. You walk onstage
and you cant hear it, definantly takes care of some of the stage rumble. And
they are definantly directional.
I am not saying other subs are not but their output between the front and back
is definantly different.

If you know of a single 12, 15 or 18 inches pro sub that have some
directivity below 80 Hz, please post references.


Meyer 650-P. There is a 6dB loss off axis. That is a signifigant difference in
any world but especially the world or PRO sound.
Almost any line array sub, DVDOSC, X-Line, M3Ds, 760 line array. The Yorkville
PS18. All of them have atleast a 6db loss at the rear.

Subs are omnidirectional somewhat, they are in the sense that Mid/Highs are
not. But even alot of subs are not truly omnidirectional, some can cover
360degrees horiz. BUT only 180 vertical at best. Look at Meyers site they or
EAW have those specs published.

Les


  #108   Report Post  
Nousaine
 
Posts: n/a
Default Subwoofer direction

(Eric Desrochers) wrote:

Eddie Runner wrote:

OK, good enough... Yes your right, the sound eminating
from the woofer does radiate out omnidirectionally...

It is very common for folks to use the omnidirectional wording
to describe our inability to localize low frequencies...

Now that were straight and in agreement on that point....

You said before that since its omnidirectionional the placement
of the woofer box is not a factor....


Hum, no. I have not talked about placement of the box, I have talked
about it's orientation, "aiming", which are two different things, of
course.

I do sound reinforcment as part of my day job and I'm into big home
theater here, so I know very well that the placement of a sub enclosure
will make or break a system.


Only if its not placed in an optimal location; which in every reasonably sized
room of the dozen+ that I've measured is in a hard corner.

But this whole thread was about the
orientation of the sub (aiming, pointing).

So I submitted that a woofer is omni-directionnal, which you seem to
agree with, therefore you cannot "aim" an omnidirectional driver, which
is where we seem to diverge opinion.

A flashlight (tweeter) can be aimed because it's directional.
A bare light bulb (woofer) cannot because it's omnidirectional.

If so, how can having a woofer shooting into the rear hatch be any
better than shooting to the rear seat?

Having the box closer to the rear of the car however is different : you
are not only aiming it, you are *moving* it, which *may* change
something due to the (possible) better loading of the driver. Just like
puting a home sub near a wall or near a corner will reinforce it.


Holy Cow; who hasn't known that placing the face of a woofer near a boundary
changes the systen tuning?


  #109   Report Post  
Eddie Runner
 
Posts: n/a
Default ha ha ha Tom changes his story! Subwoofer direction

Nousaine wrote:

Holy Cow; who hasn't known that placing the face of a woofer near a boundary
changes the systen tuning?


Holy Cow!
You must have missed that in my *cartoons*
ha ha ha

NOW, your changing your mind to say that moving a sub around in a car
WILL make a difference??

Is that what I am starting to hear from you now???

ha ha ha

in fact... ha ha ha, ha ha ha, ha ha ha!

Eddie Runner
You knew it all along!
ha ha ha ha ha ha ha ha ha ha ha ha ha ha!!
and ha ha ha ha ha
and even ha ha ha ha!

(im still laughing)


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