"Arny Krueger"
"Phil Allison"
"Bob Cain"

I've got an argument that so far has withstood some scrutiny
which shows that Doppler distortion in a myth.


** This article has all the maths re the Doppler effect in woofers.

http://www.geocities.com/kreskovs/Doppler1.html


I still haven't reviewed it thoroughly, but it looks a lot like some of
the
JAES papers I've cited recently.

But, he blew the experiment, because his results could be and probably are
dominated by AM effects.


** Kindly point to the "experiment" data in the article ??



The expeirment part of the article was deconstructed last week in that
other
forum you participate in, Phil. Forgot?


** Kindly point to the particular NG and thread ???

You are using several of the debating cheats from my list again -
Arny.



............. Phil

"Phil Allison" wrote in message

"Arny Krueger"
"Phil Allison"
"Bob Cain"

I've got an argument that so far has withstood some scrutiny
which shows that Doppler distortion in a myth.


** This article has all the maths re the Doppler effect in woofers.

http://www.geocities.com/kreskovs/Doppler1.html


I still haven't reviewed it thoroughly, but it looks a lot like some
of the JAES papers I've cited recently.

But, he blew the experiment, because his results could be and
probably are dominated by AM effects.

** Kindly point to the "experiment" data in the article ??

The exact page you cited Phil has this text and a hyperlink: "On the next
page I present experimental data supporting the results predicted by the
analysis."

The hyperlink goes to:

http://www.geocities.com/kreskovs/Doppler2.html

You must really be losing it, Phil!

The experiment part of the article was deconstructed last week in
that other forum you participate in, Phil. Forgot?

** Kindly point to the particular NG and thread ???

http://groups.google.com/groups?selm...%40comcast.com

I looked a little closer and found that you didn't participate in that
thread, Phil. Your participation in that group may be unintentional -
crossposts.

You are using several of the debating cheats from my list again
- Arny.

Just because something can be used as a cheat, doesn't mean that every use
of it is a cheat.

"Arny Krueger"
"Phil Allison"

** This article has all the maths re the Doppler effect in woofers.

http://www.geocities.com/kreskovs/Doppler1.html


I still haven't reviewed it thoroughly, but it looks a lot like some
of the JAES papers I've cited recently.

But, he blew the experiment, because his results could be and
probably are dominated by AM effects.

** Kindly point to the "experiment" data in the article ??

The exact page you cited Phil has this text and a hyperlink: "On the next
page I present experimental data supporting the results predicted by the
analysis."

The hyperlink goes to:

http://www.geocities.com/kreskovs/Doppler2.html

You must really be losing it, Phil!


** There is no hyperlink on any of the 18 pages of the article I gave the
URL for - I simply missed the one on the synopsis page. That test data is
*indeed* pathetic.

I have grave doubts now that anything in that article is actually true.

BUT it does contain the math that allegedly supports loudspeaker Doppler -
as I stated.



You are using several of the debating cheats from my list again
- Arny.


Just because something can be used as a cheat, doesn't mean that every use
of it is a cheat.


** Another debating fallacy - arguing for the general to the
particular.




.......... Phil

Impossible on first principles of acoustics. Increasing and
decreasing the air pressure results in totally predictable
changes in the velocity of the air. The are simply
proportional through the (real) characteristic impedence of air.

Can't air pressure be changed by thermal means?

Yes. That's how plasma speakers work. (I heard this straight from the mouth of
Dr. Allen Hill.)

Bob, what's the difference if the cone is moved by an electrically
supeimposed signal of two sine waves, and if it is moved electrically
by one sine wave and the whole speaker frame is moved mechanically
by another sine wave? Does the cone not go through the same motion
in both cases?

Bingo. We have now, as Dr. Land would point out, asked the right question.

"William Sommerwerck" wrote in message

Impossible on first principles of acoustics. Increasing and
decreasing the air pressure results in totally predictable
changes in the velocity of the air. The are simply
proportional through the (real) characteristic impedence of air.

Can't air pressure be changed by thermal means?

Yes. That's how plasma speakers work. (I heard this straight from the
mouth of Dr. Allen Hill.)

I guess I can then say that I've heard the thermal principle working,
straight from the mouths of a set of Plasmatronics speakers. ;-)

"Phil Allison" wrote in message

"Arny Krueger"
"Phil Allison"

** This article has all the maths re the Doppler effect in
woofers.

http://www.geocities.com/kreskovs/Doppler1.html


I still haven't reviewed it thoroughly, but it looks a lot like
some of the JAES papers I've cited recently.

But, he blew the experiment, because his results could be and
probably are dominated by AM effects.

** Kindly point to the "experiment" data in the article ??

The exact page you cited Phil has this text and a hyperlink: "On the
next page I present experimental data supporting the results
predicted by the analysis."

The hyperlink goes to:

http://www.geocities.com/kreskovs/Doppler2.html

You must really be losing it, Phil!

** There is no hyperlink on any of the 18 pages of the article I
gave the URL for - I simply missed the one on the synopsis page.

Hidden in plain sight, as it were!

That test data is *indeed* pathetic.

Thanks for agreeing.

I have grave doubts now that anything in that article is actually true.

Like I said before - it needs comparison with the relevant JAES papers.

BUT it does contain the math that allegedly supports loudspeaker
Doppler - as I stated.

No doubt.

You are using several of the debating cheats from my list again
- Arny.

Just because something can be used as a cheat, doesn't mean that
every use of it is a cheat.

** Another debating fallacy - arguing for the general to the
particular.

....and back at you, Phil.

The point you keep missing Phil, is that just because something is not an
airtight fact or based on indisputable logic, doesn't mean that there's not
some relevant truth somewhere near it. I find that obtaining truth is often
an interative process.

"Bob Cain"


Ok. If the whistle is moving at 20 miles an hour, and so is
the wind, and you are standing on the ground then the medium
is moving with respect to you. That's the same physics as
being on the moving train listening to a stationary whistle.
Doppler shift will result.



** If I read you correctly Bob:


1. The air volume in close proximity to the cone of a woofer performing low
frequency excursions moves with it as a whole - so they have essentially
the same velocity at all times.

2. That means there is no effective cone / air velocity differential as is
required to create the Doppler effect in air from the cone simultaneously
vibrating at some high frequency.

Is it as simple as that ?

If so, you have a very nice point.




................ Phil

"Arny Krueger"
"Phil Allison"

The point you keep missing Phil, is that just because something is not an
airtight fact or based on indisputable logic, doesn't mean that there's
not
some relevant truth somewhere near it.


** So says every audiophool - Arny.

There is an infinite number of things that are not quite true.

There are only a precious few that are.


I find that obtaining truth is often an interative process.


** You have demonstrated no idea how to find out the truth.

Mainly by arrogantly ****ing on those who already know what you do not.



............. Phil

"Bob Cain" wrote in message


Ok. If the whistle is moving at 20 miles an hour, and so is
the wind, and you are standing on the ground then the medium
is moving with respect to you. That's the same physics as
being on the moving train listening to a stationary whistle.
Doppler shift will result.

Also true, with no wind. The relevant variable is the relative motion
between the source and the receiver.

"Phil Allison" wrote in message


** You have demonstrated no idea how to find out the truth.

Mainly by arrogantly ****ing on those who already know what you do
not.

If irony killed we'd all be dead!

The point you keep missing Phil, is that just because something
is not an airtight fact or based on indisputable logic, doesn't mean
that there's not some relevant truth somewhere near it. I find that
obtaining truth is often an iterative process.

I'm biting my tongue...

"Arny Krueger"
"Phil Allison"

** You have demonstrated no idea how to find out the truth.

Mainly by arrogantly ****ing on those who already know what you do
not.

If irony killed we'd all be dead!


** No case in sight ......

So no case to answer.



............ Phil

"William Sommerwerck"

Arny Kruegar:

The point you keep missing Phil, is that just because something
is not an airtight fact or based on indisputable logic, doesn't mean
that there's not some relevant truth somewhere near it. I find that
obtaining truth is often an iterative process.

I'm biting my tongue...


** So you should.

When Arny is blowing it out his arse we all should stand well back.



.............. Phil

In article ,
Chris Hornbeck wrote:
On Thu, 12 Aug 2004 02:56:06 GMT, Chris Hornbeck
wrote:

I wonder how significant it may be
in the context of related questions of audibility.

On second thought, this is irrelevant ("It's not irrelevant;
it's a hippopatamus!").

Note: you have to say the quote above with the cheesiest
possible faux Viennese accent.

No, Chico did it originally with a cheesy Italian accent.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On Thu, 12 Aug 2004 07:12:30 -0400, "Arny Krueger"
wrote:

This can be restated as "air is very low impedance".
Conventional speakers operate into something close to a short
circuit.

I don't think so. Speakers are suspension and/or enclosure air compliance
loaded below resonance. They usually become cone mass-loaded around and
above resonance.

Within their passband conventional drivers contribute most of the
moving mass to the total mass (driver plus air) of the moving system.
And they are capable of exerting much greater force than can be
"used" by the high compliance of ambient air.

But because they're small compared to a wavelength, conventional
drivers have trouble imparting much particle velocity to air.
They slosh around in it, all fury and little sound, signifying
nothing.

The high force to velocity ratio describes a high mechanical
impedance compared to air. Conventional drivers are muscle-bound.

A driver operating into an acoustical short circuit would be motionless.

Actually a conventional driver would move very similarly in a vacuum.
I think; never tried it.

Chris Hornbeck

On Thu, 12 Aug 2004 23:09:49 +1000, "Phil Allison"
wrote:


"Bob Cain"


Ok. If the whistle is moving at 20 miles an hour, and so is
the wind, and you are standing on the ground then the medium
is moving with respect to you. That's the same physics as
being on the moving train listening to a stationary whistle.
Doppler shift will result.



** If I read you correctly Bob:


1. The air volume in close proximity to the cone of a woofer performing low
frequency excursions moves with it as a whole - so they have essentially
the same velocity at all times.

2. That means there is no effective cone / air velocity differential as is
required to create the Doppler effect in air from the cone simultaneously
vibrating at some high frequency.

Is it as simple as that ?

If so, you have a very nice point.


Yes, but only for about a second.

The distance between the transmitter and reciever is still being
changed. If you consider two positions of the speaker cone, A ="in" ,
B="out" and a microphone at C. It basically does not matter what the
speed of air or sound,or the path is between A and C since it is also
common to B to C apart from the bit ( A to B ). Sound from B arrives
before sound from A since it is nearer to C so there is a phase
displacement which is being modulated at 50Hz and it is simply equal
to the displacement of the speaker cone converted by frequency and
speed of sound, to an angular displacement of the cone.= (cone
displacement /wavelength@50Hz ) * 2 * PI radians.The linear
displacement is converted to phase modulation and therefore frequency
modulation.

On second thought, this is irrelevant ("It's not irrelevant;
it's a hippopatamus!").
Note: you have to say the quote above with the cheesiest
possible faux-Viennese accent.

"Some say the title of this song is irrelevant. But it's not irrelevant -- it's
a hippopotamus!"

"Mud, mud, glorious mud.
Sling as much as you like -- it'll stir up the blood!"

Chris Hornbeck wrote:

Also the modulated arc "ion" speakers and the modulated flame
(I **** thee not) speakers used in Vietnam for propaganda flights.

The latter weren't high fi but were loud enough to allow you to
fly high enough to not be seen. A definite advantage given the
mood of the crowd.

You got a cite on this, or even the name of a manufacturer? I know some
aircraft guys who would be very interested in this.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On 12 Aug 2004 11:05:42 -0400, (Scott Dorsey) wrote:

You got a cite on this, or even the name of a manufacturer? I know some
aircraft guys who would be very interested in this.

Sorry, no. Pictures I've seen looked very
much like the double-bent-horn paging speakers, only much
bigger. They talked about 140 dB SPL or so, IIRC.

I kinda remember they modulated with a solenoid operated
valve in the fuel line. But my memory is notoriously
flakey.

Chris Hornbeck

On Thu, 12 Aug 2004 07:56:54 -0700, "William Sommerwerck"
wrote:

"Some say the title of this song is irrelevant. But it's not irrelevant -- it's
a hippopotamus!"

"Mud, mud, glorious mud.
Sling as much as you like -- it'll stir up the blood!"

"His inamorata,
Adjusted her garter,"

But I didn't know they were quoting Chico! Thanks, Scott.

Chris Hornbeck

Chris Hornbeck wrote:

But I didn't know they were quoting Chico! Thanks, Scott.

Chico: Judge, what's a gotta four legs and a trunk?

Groucho: That's irrelevant!

Chico: That's a right!
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Also the modulated-arc "ion" speakers and the modulated flame
(I **** thee not) speakers used in Vietnam for propaganda flights.

Flame speakers actually date to the late 19th century. They worked, but were
noisy.

There have been several ionic speakers, most notably the DuKane Ionovac tweeter,
and the Hill Plasmatronic speaker, which was ionic from 700Hz up.

"His inamorata,
Adjusted her garter,"

But I didn't know they were quoting Chico!

They weren't.

On Thu, 12 Aug 2004 07:16:34 -0400, "Arny Krueger"
wrote:

I see two flaws here. First is that the FM exists *at the
diaphragm* and is independent of media.

The FM exists at the receiver or listener. If the speaker and the listener
have no relative velocity, no Doppler.

People who ride on trains don't hear the whistle of their train as being
Doppler-shifted.

You raise a very interesting point and I'm not smart enough to
figure it out myself.

Suppose the listener were mounted on a (very strong) diaphragm
driven by the same signal, EQ'ed and time-delayed, as the source
diaphragm, in order to cancel out their relative movement.

Would the listener still hear the FM sidebands?

Chris Hornbeck

Arny Krueger wrote:

"Bob Cain" wrote in message


Arny Krueger wrote:



Arny, when you start mixing distributed non-linearities such
as that in the surround, that of cone distortion, that of
the magnetic circuit, etc. It is not generally possible to
describe the resulting form of distortion.


What, whether it is AM or FM or what proportion of which?


Whether it is even formally describable.


It's formally describable!

I don't mean whether simple FM is describable but whether
the net effect of all the interacting sources of distortion
in a loudspeaker is describable in order to know whether
they might be doing some FM on the way to the piston or
through it before the force gets to the piston/air
interface. If there is I'd love to see it.

The hell they don't. If what is generating the data to be
measured cannot be characterized then neither can the data.


Well, all we need to know is "This is the sound that is coming out of the
front of the speaker".

If all you are doing is measuring it. If you wish to draw
any conclusions about what made it that way then you need a
whole lot more than just measurement, unless the conclusions
are of the broadest nature. For example, "the thing
distorts." What if the effect you are looking for was
actually contained, for some reason and to some degree, in
the input, driving signal? Does that not need to be
accounted for?



Lets go down your list:

(1) that in the surround - doesn't matter where the Doppler comes
from, just that it is.


I don't follow this.


What does a speaker do? It makes sound. What do we do with speakers? We put
them in boxes. To make things simple let's consider a sealed box. The sealed
box is there to ensure that the only sound we hear comes out of the front of
the speaker, not its back. Therefore, all we need to do is characterize the
sound that is coming out of the front of the speaker.

Unless one is trying to disect that to see what is doing
what to arrive at the result.



(2) that of cone distortion - doesn't matter where the Doppler comes
from, just that it is.'


This either.


Same story. All we need to do is characterize the sound coming out of the
front of the speaker, regardles of its source.

Ya know, Arny I really have a hard time beliving that you as
an experimentalist are really this naive. All I'm doing in
this sub-thread is describing the fundamentals of scientific
investigation and I shouldn't need to do that.



(3) the magnetic circuit - not moving, so it can't cause Doppler


I understand this one. The question remains whether FM can
be ruled out of an active system that has these forms of
distortion in a distributed and interacting fashion. Can it?


The general case is that there is both AM & FM distortion. The purpose of
the measurement is to determine where or not there is FM distortion.

The purpose, for this discussion at least, is to determine
if it's due to "Doppler distortion" or can be accounted for
by the intrinsic distortion within the driver itself.

We get pretty clean isolated spectral lines from real-world
measurements. Guess what that says about the simulation?


What's it say about the system under test?


It's performing a lot different than the simulation that predicts chaos.

Exactly. Show me a model that can be physically related to
what is supposedly happening that doesn't.

What does it specifically say about Doppler distortion?


Our test finds some Doppler distortion.

How do you know it is "Doppler distortion" all you know is
that you seem to be seeing evidence of frequency modulation.

We don't need a working theory to have believable experimental
results.


Absolutely agreed, but to have a believable experimental
result all factors that can contribute to the data in the
same way that the phenomenon being investigated can must
either be completely characterized or eliminated. This is
fundamental.


It's not a problem here because we do have a working, believeable theory
about loudspeaker Doppler.

It's a problem here precisely because we don't have that
theory (and should by now.) There is nothing to compare
experiment against and no attention given to isolating the
effect under investigation so that we even could.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

Kurt Riemann wrote:



Except that I disagree that there IS any velocity added to the higher
wave. The wave IS velocity. No more, no less. Complex but coherent.

Exactly, precisely and completely.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

Arny Krueger wrote:


Doppler has not escaped the attention of the technical community. There are
a number of JAES papers about it.

Citations, please.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

Ben Bradley wrote:



I don't think a question of how it distinguishes is
meaninful. The physics is simply different if the generator
is moving within the medium or moving it.


How so, Bob?

By inspection. They are obviously different physical
situations. It remains to be shown that they are equivalent
in any sense and I think that's because it isn't possible.



That's the problem. There is no difference.

Ah, but there is.


Bob, what's the difference if the cone is moved by an electrically
supeimposed signal of two sine waves, and if it is moved electrically
by one sine wave and the whole speaker frame is moved mechanically by
another sine wave? Does the cone not go through the same motion in
both cases?

Gotta chew on this one and on the rest of your challenge.
It's a darned good one and I don't wanna just jerk my knee
or wave my hands.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

William Sommerwerck wrote:

Bob, what's the difference if the cone is moved by an electrically
supeimposed signal of two sine waves, and if it is moved electrically
by one sine wave and the whole speaker frame is moved mechanically
by another sine wave? Does the cone not go through the same motion
in both cases?


Bingo. We have now, as Dr. Land would point out, asked the right question.

Agreed, I think. :-)


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

Phil Allison wrote:


** If I read you correctly Bob:


1. The air volume in close proximity to the cone of a woofer performing low
frequency excursions moves with it as a whole - so they have essentially
the same velocity at all times.

2. That means there is no effective cone / air velocity differential as is
required to create the Doppler effect in air from the cone simultaneously
vibrating at some high frequency.

Is it as simple as that ?

Yes, I think. Without pondering it deeply, it seems to be
an accurate, yet different, way to state it and at least
tentatively I think they are equivalent.

How's that for a noncomittal affirmative? :-)


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

Bob Cain wrote:
Phil Allison wrote:

1. The air volume in close proximity to the cone of a woofer
performing low
frequency excursions moves with it as a whole - so they have essentially
the same velocity at all times.

2. That means there is no effective cone / air velocity differential
as is
required to create the Doppler effect in air from the cone simultaneously
vibrating at some high frequency.

Is it as simple as that ?

Yes, I think. Without pondering it deeply, it seems to be an accurate,
yet different, way to state it and at least tentatively I think they are
equivalent.

Hmm, OK, I haven't been closely following the discussion, but if the air
at any distance[1] from the cone is always moving at absolutely the same
velocity as the cone, then that would imply that the sound wave propagates
at infinite speed[2], i.e. that the speed of sound is infinite, right?

But if it's essentially the same speed, then doesn't that just mean it's
a very close approximation? But we already agreed doppler distortion
(if it exists) is very small.

- Logan

[1] Non-zero, finite distance, I mean.
[2] Assuming the cone is changing speeds. Which, hopefully, it is.

On Thu, 12 Aug 2004 15:19:45 -0700, Bob Cain
wrote:

Doppler has not escaped the attention of the technical community. There are
a number of JAES papers about it.

Citations, please.

The papers by Klipsch, and by Allison and Villchur, toe their
respective party lines pretty closely audibility.

Colloms' _High Performance Loudspeakers_ gives a good
overview and very good references. Many are offended by
its tone, but that's the par on this course.

Good fortune, great topic, thanks,

Chris Hornbeck

On or about Wed, 11 Aug 2004 13:10:23 GMT, Carey Carlan allegedly wrote:

As a non-mathematical type I understood Doppler distortion to be caused
when a high frequency was generated by a driver already in motion with a
low frequency.

The example was a woofer moving full excursion on a very low tone while
generating a higher tone. Let's do an extreme case of a 10 Hz excursion
and a 1000 Hz tone. Every 20th of a second (change in direction at 10 Hz)
the pitch of the 1000 Hz tone would change as its vibrating medium (the
woofer cone) changed from moving toward the listener to moving away.

Thanks. That helps me get a handle on this.

If they are real sounds, and were captured by a single microphone, then a
similar doppler shifting would be encoded by the microphone, so the
speaker would simply be decoding that, and effectively restoring the HF
tone to it's original timing. Of course the mic would typically have less
excursion than the speaker, but if frequency response was flat for both,
everything should be in the same balance.

If such a doppler encoded signal from a single mic is then reproduced on a
typical two way speaker system, then the hf component would have doppler
shifting that does not get decoded. But as others have mentioned,
multiway speakers would reduce that modulating effect, so perhaps are more
suited to reproducing material that has been mixed from widely different
sources so would not have the natural doppler encoding.

Sounds like a good argument for minimalist recording (one of many), and
don't touch that eq. at all, or you'll ruin everything.


Noel Bachelor noelbachelorAT(From:_domain)
Language Recordings Inc (Darwin Australia)

"Bob Cain"
Phil Allison wrote:

** If I read you correctly Bob:


1. The air volume in close proximity to the cone of a woofer performing
low
frequency excursions moves with it as a whole - so they have
essentially
the same velocity at all times.

2. That means there is no effective cone / air velocity differential as
is
required to create the Doppler effect in air from the cone
simultaneously
vibrating at some high frequency.

Is it as simple as that ?

Yes, I think. Without pondering it deeply, it seems to be
an accurate, yet different, way to state it and at least
tentatively I think they are equivalent.



** Now I am interested in the **mechanism** that allows that volume air
moving in unison with a woofer cone with a high frequency pressure wave
travelling through it to *transfer* that high frequency wave to the still
air further away.





.............. Phil

"Bob Cain"
Phil Allison wrote:

** If I read you correctly Bob:


1. The air volume in close proximity to the cone of a woofer performing
low
frequency excursions moves with it as a whole - so they have
essentially
the same velocity at all times.

2. That means there is no effective cone / air velocity differential as
is
required to create the Doppler effect in air from the cone
simultaneously
vibrating at some high frequency.

Is it as simple as that ?

Yes, I think. Without pondering it deeply, it seems to be
an accurate, yet different, way to state it and at least
tentatively I think they are equivalent.



** Now I am interested in the **mechanism** that allows that volume air
moving in unison with a woofer cone with a high frequency pressure wave
travelling through it to *transfer* that high frequency wave to the still
air further away.





.............. Phil

FWIW, I just slogged through the thread on rec.audio.tech
(much improved these days!) and found that it contained a
simple foolproof hardware test solution, by Paul Guy.

Since it didn't involve computers it was ignored. Gosh.

Chris Hornbeck

FWIW, I just slogged through the thread on rec.audio.tech
(much improved these days!) and found that it contained a
simple foolproof hardware test solution, by Paul Guy.

Since it didn't involve computers it was ignored. Gosh.

Chris Hornbeck

Phil Allison wrote:

"Bob Cain"

I've got an argument that so far has withstood some scrutiny
which shows that Doppler distortion in a myth.




** This article has all the maths re the Doppler effect in woofers.

http://www.geocities.com/kreskovs/Doppler1.html

Thanks, I'll give it a study. I've already found a wrong
working assumption, that the sound pressure created by a
driver is proportional to its acceleration rather than its
velocity and don't know yet how far that pervades the analysis.

That is the simplest refutation of Doppler, BTW. If the
pressure it creates is proportional to its velocity, which I
will believe until I see it proved otherwise, then since
velocities add linearly so will pressure and there can't be
modulation products.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

Phil Allison wrote:

"Bob Cain"

I've got an argument that so far has withstood some scrutiny
which shows that Doppler distortion in a myth.




** This article has all the maths re the Doppler effect in woofers.

http://www.geocities.com/kreskovs/Doppler1.html

Thanks, I'll give it a study. I've already found a wrong
working assumption, that the sound pressure created by a
driver is proportional to its acceleration rather than its
velocity and don't know yet how far that pervades the analysis.

That is the simplest refutation of Doppler, BTW. If the
pressure it creates is proportional to its velocity, which I
will believe until I see it proved otherwise, then since
velocities add linearly so will pressure and there can't be
modulation products.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein