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ChrisCoaster ChrisCoaster is offline
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Default Want to design a 3-way speaker with "extreeeem" excursion

Just thought I'd throw this out there - partially to punctuate the
endless Google Groups posts hocking knock-off handbags and Nike
merchandise - and to see if this idea might actually go somewhere(!)

I'm thinking about a speaker line, both a bookshelf and a
floorstanding model. Standard 8-16ohm impedance, current state of art
materials, with as low-resonance a cabinet as humanly possible.
Speaker would be a sealed unit, capable of handling anywhere from
50-200W.

The two key differences a

1. All drivers(2 in the bookshelf and 3 for the floor-standing) would
be in the same plane. That is, the mid and hf elements would be set
back so as to be "in lne" with the resting position of the woofer.
This is not new, and many mfgs have done it for 20 years or more.

2.(the big one!) - The woofer - and the midrange in the case of the
floor-standing, would have a range of travel unprecedented for their
size.

I'm proposing a 6" woofer and 1"dome tweeter for the bookshelf, and a
7"woofer, 3"mid, and same 1"dome tweeter for the floor model.

I'm talking about both woofers having at least a 1" high-profile butyl-
rubber surround that would allow visible movement even when driven
mildly. The midrange might also be visibly moved, especially on
tracks with strong transient drums(think early-to-mid era Genesis or
just about anything from LZ).

Of course an area in which I have no expertise would have to be
advanced - and that is dampening. For a speaker like this the cones
might end up ringing like a bell!

My theory is that small rigid cones with high excursion move as much
air as effectively as a huge cone with less excursion and perhaps not
as structurally stiff.

-CC
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UnsteadyKen UnsteadyKen is offline
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Default Want to design a 3-way speaker with "extreeeem" excursion

ChrisCoaster said...

My theory is that small rigid cones with high excursion move as much
air as effectively as a huge cone with less excursion and perhaps not
as structurally stiff.


It might work at very low frequencies less than 10 hz perhaps.

In the normal frequency range, 500hz for example if the cones were to
use the full 1 inch travel yet still produce an accurate representation
of the waveform presented to them they would have to accelerate and
decelerate at values approaching infinity or thereabouts thus implying
a cone with no mass would be required.


--
Ken O'Meara
http://www.btinternet.com/~unsteadyken/
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ChrisCoaster ChrisCoaster is offline
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Default Want to design a 3-way speaker with "extreeeem" excursion

On Oct 30, 9:39*am, UnsteadyKen wrote:
ChrisCoaster said...

My theory is that small rigid cones with high excursion move as much
air as effectively as a huge cone with less excursion and perhaps not
as structurally stiff.


It might work at very low frequencies less than 10 hz perhaps.

In the normal frequency range, 500hz for example if the cones were to
use the full 1 inch travel yet still produce an accurate representation
of the waveform presented to them they would have to accelerate and
decelerate at values approaching infinity or thereabouts thus implying
a cone with no mass would be required.

--
Ken O'Mearahttp://www.btinternet.com/~unsteadyken/

_____________

Of course, I didn't specify that the full 1 inch(or more!) of travel
might not be reached until you are achieving at least 70dB spls. I've
always believed, growing up, that the speaker that moves more air
yields more lifelike results.

-CC
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UnsteadyKen UnsteadyKen is offline
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Default Want to design a 3-way speaker with "extreeeem" excursion

Dick Pierce said...

Snipped the most excellent work.

Hardly "infinite",
hardly "thereabout infinite", and, indeed, not even in
the same zip code.


Thanks Dick that was most informative and your point is well taken by
this bear of little brain. In future I shall use "quite large"

One small question. Would it take a similar amount of power to halt the
driver as it approaches the end of travel ready for the return journey?
It seems to me that more would be required as we now have the mass of
the driver plus the velocity imparted by the acceleration?
Or have I misunderstood how amplifiers control the drivers?
Which is very likely so.

--
Ken O'Meara
http://www.btinternet.com/~unsteadyken/
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ChrisCoaster ChrisCoaster is offline
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Default Want to design a 3-way speaker with "extreeeem" excursion

On Oct 30, 7:15*pm, UnsteadyKen wrote:
Dick Pierce said...

Snipped the most excellent work.

Hardly "infinite",
hardly "thereabout infinite", and, indeed, not even in
the same zip code.


Thanks Dick that was most informative and your point is well taken by
this bear of little brain. In future I shall use "quite large"

One small question. Would it take a similar amount of power to halt the
driver as it approaches the end of travel ready for the return journey?
It seems to me that more would be required as we now have the mass of
the driver plus the velocity imparted by the acceleration?
Or have I misunderstood how amplifiers control the drivers?
Which is very likely so.

--
Ken O'Mearahttp://www.btinternet.com/~unsteadyken/

____________________

In general terms, I guess that has to do with both the dampening
characteristics of the speaker material itself, and the
dampening(electrical) function of the amp.

The latter would have to be explained in kindergarten terms for me, at
least. Dick Pierce?

-CC


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Peter Larsen[_3_] Peter Larsen[_3_] is offline
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Default Want to design a 3-way speaker with "extreeeem" excursion

ChrisCoaster wrote:

The two key differences a


1. All drivers(2 in the bookshelf and 3 for the floor-standing) would
be in the same plane. That is, the mid and hf elements would be set
back so as to be "in lne" with the resting position of the woofer.
This is not new, and many mfgs have done it for 20 years or more.


And lo and behold, it actually is a poorer design than having them all
integrated in the same flat surface because of the additional diffraction
edges and the strange multivariable baffle diffraction steps you end up
with.

2.(the big one!) - The woofer - and the midrange in the case of the
floor-standing, would have a range of travel unprecedented for their
size.


Dick said a lot of what can be said. However look at the "known good"
loudspeakers, those are in my experience characterized by minimizing the
excursion via a large effient area. This because it is easier to get a
suspension quasi linear within a small range than within a large range.

I'm proposing a 6" woofer and 1"dome tweeter for the bookshelf, and a
7"woofer, 3"mid, and same 1"dome tweeter for the floor model.


Bass unit size in itself needs to be seen in the context of box size,
intended bandwidth and obtainable efficiency.

I'm talking about both woofers having at least a 1" high-profile
butyl- rubber surround that would allow visible movement even when
driven mildly.


It is all about displacement volume.

The midrange might also be visibly moved, especially
on tracks with strong transient drums(think early-to-mid era Genesis
or just about anything from LZ).


Depends on what you call midrange.

Of course an area in which I have no expertise would have to be
advanced - and that is dampening. For a speaker like this the cones
might end up ringing like a bell!


Your vision of a loudspeaker cone is too simple, rigid cones are generally
more of a problem than of a solution because of exactly that problem. You do
not get a good directional diagram without the cone decoupling its outer
area when reproducing high frequencies, whatever that is in the context of
its working range. If you insist on using loudspeaker units only in their
piston range you end up with a 10 way system, ie. with 9 crossover-points
you need to get "just rightų".

My theory is that small rigid cones with high excursion move as much
air as effectively as a huge cone with less excursion and perhaps not
as structurally stiff.


Yes, that is a good "volume displacement" understanding, but a small cone
with little or hardly any excursion coupled via a horn has both advantages,
and then quite a few other problems.

It is always a matter of multiple tradeoff, and the art of the designer is
where to place them. The perfect loudspeaker has zero area, since area is
problematic, and zero excursion since excursion is problematic, but with
excursion and area both approaching zero the sound output does likewise.

-CC


Kind regards

Peter Larsen



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UnsteadyKen UnsteadyKen is offline
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Default Want to design a 3-way speaker with "extreeeem" excursion

Dick Pierce said...


You wouldn't be the first. And you'd be in the same league
as many loudspeaker "designers."


Thank you Dick. It is kind of you to take the trouble to answer these
daft questions.



--
Ken O'Meara
http://www.btinternet.com/~unsteadyken/
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Bill Graham Bill Graham is offline
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Default Want to design a 3-way speaker with "extreeeem" excursion


"UnsteadyKen" wrote in message
m...
Dick Pierce said...


You wouldn't be the first. And you'd be in the same league
as many loudspeaker "designers."


Thank you Dick. It is kind of you to take the trouble to answer these
daft questions.

He may have to use one of your speakers in the future....:^)

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David Nebenzahl David Nebenzahl is offline
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Default Want to design a 3-way speaker with "extreeeem" excursion

On 10/30/2010 6:20 AM ChrisCoaster spake thus:

Just thought I'd throw this out there - partially to punctuate the
endless Google Groups posts hocking knock-off handbags and Nike
merchandise - and to see if this idea might actually go somewhere(!)

I'm thinking about a speaker line, both a bookshelf and a
floorstanding model. Standard 8-16ohm impedance, current state of art
materials, with as low-resonance a cabinet as humanly possible.
Speaker would be a sealed unit, capable of handling anywhere from
50-200W.

The two key differences a

1. All drivers(2 in the bookshelf and 3 for the floor-standing) would
be in the same plane. That is, the mid and hf elements would be set
back so as to be "in lne" with the resting position of the woofer.
This is not new, and many mfgs have done it for 20 years or more.

2.(the big one!) - The woofer - and the midrange in the case of the
floor-standing, would have a range of travel unprecedented for their
size.


Heh; this reminds me of my own thinking as a kid fooling around with
building speakers[1] and thinking of how to make the "ultimate woofer".

So as absurd as this proposal seems to have been, it raises some
interesting questions (non-absurd, I trust). In particular, if one were
to try to design such an "ultimate woofer", what would be the main
limiting factors to powerful low-frequency response?

1. Cone size (area)
2. Cone compliance (maximum excursion)
3. Motor strength (voice coil size, power capacity, magnet size)
4. Cabinet size & shape
5. Other

(Hopefully Dick Pierce might be interested enough to answer this.)


[1] My first was an acoustic-suspension bookshelf system, built to plans
in Popular Electronics. I remember getting the 6" woofers, really cheap,
from McGee Radio in Kansas City. They're long gone, of course; anyone
else remember this company? They had an amazing selection of raw
speakers and all kinds of other electronic stuff.


--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.

- Comment from an article on Antiwar.com (http://antiwar.com)
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Arny Krueger Arny Krueger is offline
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Default Want to design a 3-way speaker with "extreeeem" excursion

"ChrisCoaster" wrote in message


I'm thinking about a speaker line, both a bookshelf and a
floorstanding model. Standard 8-16ohm impedance, current
state of art materials, with as low-resonance a cabinet
as humanly possible. Speaker would be a sealed unit,
capable of handling anywhere from 50-200W.


Check the Paradigm catalog for suitable alternatives.

The two key differences a


1. All drivers(2 in the bookshelf and 3 for the
floor-standing) would be in the same plane.


Which same plane?

Are you talking about the plane that the speaker driver chassis are mounted
on or the plane of the acoustic centers?



2.(the big one!) - The woofer - and the midrange in the
case of the floor-standing, would have a range of travel
unprecedented for their size.


If their travel is unprecidented, then it never ever existed. At this point
drivers are available with excursions that exceed any possible practical
need at home. IOW you are asking for something that not only has never been
done, but also serves no practical purpose.



I'm proposing a 6" woofer and 1"dome tweeter for the
bookshelf, and a 7"woofer, 3"mid, and same 1"dome tweeter
for the floor model.


Why does the floor-stander need to be 3-way?

I'm talking about both woofers having at least a 1"
high-profile butyl- rubber surround that would allow
visible movement even when driven mildly.


If there is visible movement when the speaker is driven mildly, it would
appear to me that there is likely some design fault. Well designed speakers
move their cones as little as possible consistent with undistored output.

The midrange
might also be visibly moved, especially on tracks with
strong transient drums(think early-to-mid era Genesis or
just about anything from LZ).


This is a rediculous cosmetic-only requirement.

Of course an area in which I have no expertise would have
to be advanced - and that is dampening. For a speaker
like this the cones might end up ringing like a bell!


The operative phrase would appear to be "no expertise". A knowlegable person
would simply not ask for what you are demanding.

My theory is that small rigid cones with high excursion
move as much air as effectively as a huge cone with less
excursion and perhaps not as structurally stiff.


Structural stiffness as perceived by you would appear to be yet another
ill-advised cosmetic requirement.




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David Nebenzahl David Nebenzahl is offline
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Default Want to design a 3-way speaker with "extreeeem" excursion

On 11/1/2010 12:17 PM ChrisCoaster spake thus:

On Nov 1, 7:52 am, "Arny Krueger" wrote:

"ChrisCoaster" wrote in message


I'm thinking about a speaker line, both a bookshelf and a
floorstanding model. Standard 8-16ohm impedance, current state
of art materials, with as low-resonance a cabinet as humanly
possible. Speaker would be a sealed unit, capable of handling
anywhere from 50-200W.

The midrange might also be visibly moved, especially on tracks
with strong transient drums(think early-to-mid era Genesis or
just about anything from LZ).


This is a rediculous cosmetic-only requirement.


[snip]

Sigh...Why couldn't everyone be more like Dick Pierce?(a little heavy
on the math, but otherwise takes time to lay it out in plain terms)


Arny is what I'd call a sourpuss. Very knowledgable, yes, but then, so
is Dick Pierce, who was kind enough to indulge quite a bit of ignorance
here (including my own) in a civil way. If you can't discuss things on
their lofty level, folks like Arny just turn up their noses at you.

Once you're aware of this it ceases to be a problem.


--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.

- Comment from an article on Antiwar.com (http://antiwar.com)
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Arny Krueger Arny Krueger is offline
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Default Want to design a 3-way speaker with "extreeeem" excursion

"David Nebenzahl" wrote in message
.com
On 11/1/2010 12:17 PM ChrisCoaster spake thus:

On Nov 1, 7:52 am, "Arny Krueger"
wrote:
"ChrisCoaster" wrote in message


I'm thinking about a speaker line, both a bookshelf
and a floorstanding model. Standard 8-16ohm
impedance, current state of art materials, with as
low-resonance a cabinet as humanly possible. Speaker
would be a sealed unit, capable of handling anywhere
from 50-200W. The midrange might also be visibly moved, especially
on tracks with strong transient drums(think
early-to-mid era Genesis or just about anything from
LZ).

This is a rediculous cosmetic-only requirement.


[snip]


Sigh...Why couldn't everyone be more like Dick Pierce?(a
little heavy on the math, but otherwise takes time to
lay it out in plain terms)


Math is by definition *Not* "plain terms".

Arny is what I'd call a sourpuss.


Nahh, just being very blunt because it seems to be requried to penetrate all
of the fuzzy thinking.

Very knowledgable, yes,
but then, so is Dick Pierce, who was kind enough to
indulge quite a bit of ignorance here (including my own)
in a civil way. If you can't discuss things on their
lofty level, folks like Arny just turn up their noses at
you.


Actually Chris, it is you who are turning your nose up at me.

Once you're aware of this it ceases to be a problem.


If it wasn't a problem, you wouldn't be libelling me this way.

Just another case of a good deed failing to go unpunished. ;-)


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Bill Graham Bill Graham is offline
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Default Want to design a 3-way speaker with "extreeeem" excursion


"Arny Krueger" wrote in message
...
"David Nebenzahl" wrote in message
.com
On 11/1/2010 12:17 PM ChrisCoaster spake thus:

On Nov 1, 7:52 am, "Arny Krueger"
wrote:
"ChrisCoaster" wrote in message


I'm thinking about a speaker line, both a bookshelf
and a floorstanding model. Standard 8-16ohm
impedance, current state of art materials, with as
low-resonance a cabinet as humanly possible. Speaker
would be a sealed unit, capable of handling anywhere
from 50-200W. The midrange might also be visibly moved, especially
on tracks with strong transient drums(think
early-to-mid era Genesis or just about anything from
LZ).

This is a rediculous cosmetic-only requirement.


[snip]


Sigh...Why couldn't everyone be more like Dick Pierce?(a
little heavy on the math, but otherwise takes time to
lay it out in plain terms)


Math is by definition *Not* "plain terms".


On the contrary. Math is by definition the only "plain term". that's exactly
why I majored in it. It's called "quantitative", (rather than qualitative.)
And, it tells the true story every time. Have you ever tried buying a box or
leather case for some item you have, like a tape measure, or a pocket knife?
You can Google up a dozen of them, and the dimensions won't be on any one of
them. I call it "dimentionphobia", or the dumbing down of America.

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David Nebenzahl David Nebenzahl is offline
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Default Want to design a 3-way speaker with "extreeeem" excursion

On 11/2/2010 4:29 AM Arny Krueger spake thus:

"David Nebenzahl" wrote in message
.com

Very knowledgable, yes,
but then, so is Dick Pierce, who was kind enough to
indulge quite a bit of ignorance here (including my own)
in a civil way. If you can't discuss things on their
lofty level, folks like Arny just turn up their noses at
you.


Actually Chris, it is you who are turning your nose up at me.


You replied to me, yet you called me Chris.

I think you have a slight attribution problem there.


--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.

- Comment from an article on Antiwar.com (http://antiwar.com)
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