"Bob Cain" wrote in message

Bob Cain wrote:



Arny Krueger wrote:


Sorry Bob, but I'm not buying.


How about this, then:

1) It is the bulk velocity, the flow of air, at the rest position
that propagates out as the velocity wave.

Frankly, over my head.

2) The bulk velocity at the rest position is the same as the surface
velocity of the piston.

Frankly, over my head.

And, finally:

3) In the frame of reference of the rest position of the
piston, no Doppler shift can be observed.

That seems wrong, because the following is right:

In the frame of reference of the piston, no Doppler shift can be observed.

That's the listener riding the same train as the whistle.

"Arny Krueger" wrote in message
news
"Bob Cain" wrote in message

Bob Cain wrote:



Arny Krueger wrote:


Sorry Bob, but I'm not buying.


How about this, then:

1) It is the bulk velocity, the flow of air, at the rest position
that propagates out as the velocity wave.

Frankly, over my head.

2) The bulk velocity at the rest position is the same as the surface
velocity of the piston.

Frankly, over my head.

And, finally:

3) In the frame of reference of the rest position of the
piston, no Doppler shift can be observed.

That seems wrong, because the following is right:

In the frame of reference of the piston, no Doppler shift can be
observed.

That's the listener riding the same train as the whistle.


It seems to me that the train/whistle anology is not a valid one for this
purpose, because the train's motion and the whistle's sound are not being
reproduced by the same source, as happens in a loudspeaker producing a
complex waveform.
If you make a recording of the train approaching and receeding from your
listening position and play it back, you will hear exactly the same Doppler
shift you heard when the train went by, and this can be confirmed by
measurement. Conversely, if you make a recording of the whistle from the
train and play it back on a speaker moving down the tracks at the same
velocity as the train, you will hear the same doppler shift you heard from
the passing train, even though there is no shift in the actual recording.
The above logic actually has little to do with Doppler distortion in a
speaker, but the fact remains that the train/whistle in not a valid anology!
Making the assumption that a speaker produces Doppler shift because a
whistle on a moving train does is a rationalization not based on the actual
physical facts. Even moving the whistle back and forth in approximation of a
moving speaker cone is not a valid anology, because the whistle's back and
forth motion is not generated by the sound coming from the whistle, as it
would be in a speaker reproducing a complex waveform. You're actually
dealing with two separate sources producing separate waveforms. Mounting the
whistle on the speaker cone still won't be a valid anology because the
waveforms are not being reproduced by the same mechanism, two separate
sources again.
The only valid anology for what happens with a speaker reproducing a
complex waveform would be some other single entity that is capable of
reproducing the same complex waveform. Any suggestions?

"Porky"

"Arny Krueger"

That's the listener riding the same train as the whistle.


It seems to me that the train/whistle anology is not a valid one for
this
purpose, because the train's motion and the whistle's sound are not being
reproduced by the same source, as happens in a loudspeaker producing a
complex waveform.


** How so ? The whiste is mounted on the train.


If you make a recording of the train approaching and receeding from your
listening position and play it back, you will hear exactly the same
Doppler
shift you heard when the train went by, and this can be confirmed by
measurement. Conversely, if you make a recording of the whistle from the
train and play it back on a speaker moving down the tracks at the same
velocity as the train, you will hear the same doppler shift you heard from
the passing train, even though there is no shift in the actual recording.


** No kidding.


The above logic actually has little to do with Doppler distortion in a
speaker, but the fact remains that the train/whistle in not a valid
anology!


** I saw no relevant facts go by - must have just whizzed past on an
express train .......


Making the assumption that a speaker produces Doppler shift because a
whistle on a moving train does is a rationalization not based on the
actual
physical facts.


** You rationalisations are far more extensive and non logical.



Even moving the whistle back and forth in approximation of a
moving speaker cone is not a valid anology, because the whistle's back and
forth motion is not generated by the sound coming from the whistle, as it
would be in a speaker reproducing a complex waveform.


** Huh ? Since when is a cone's motion *produced* by sound ???



You're actually dealing with two separate sources producing separate
waveforms.
Mounting the whistle on the speaker cone still won't be a valid anology
because the
waveforms are not being reproduced by the same mechanism, two separate
sources again.

The only valid anology for what happens with a speaker reproducing a
complex waveform would be some other single entity that is capable of
reproducing the same complex waveform. Any suggestions?


** Lay off the weed.




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

"Phil Allison" wrote in message
...

"Porky"

"Arny Krueger"

That's the listener riding the same train as the whistle.


It seems to me that the train/whistle anology is not a valid one for
this
purpose, because the train's motion and the whistle's sound are not
being
reproduced by the same source, as happens in a loudspeaker producing a
complex waveform.


** How so ? The whiste is mounted on the train.


If you make a recording of the train approaching and receeding from your
listening position and play it back, you will hear exactly the same
Doppler
shift you heard when the train went by, and this can be confirmed by
measurement. Conversely, if you make a recording of the whistle from the
train and play it back on a speaker moving down the tracks at the same
velocity as the train, you will hear the same doppler shift you heard
from
the passing train, even though there is no shift in the actual
recording.


** No kidding.


The above logic actually has little to do with Doppler distortion in a
speaker, but the fact remains that the train/whistle in not a valid
anology!


** I saw no relevant facts go by - must have just whizzed past on an
express train .......


Making the assumption that a speaker produces Doppler shift because a
whistle on a moving train does is a rationalization not based on the
actual
physical facts.


** You rationalisations are far more extensive and non logical.



Even moving the whistle back and forth in approximation of a
moving speaker cone is not a valid anology, because the whistle's back
and
forth motion is not generated by the sound coming from the whistle, as
it
would be in a speaker reproducing a complex waveform.


** Huh ? Since when is a cone's motion *produced* by sound ???



You're actually dealing with two separate sources producing separate
waveforms.
Mounting the whistle on the speaker cone still won't be a valid anology
because the
waveforms are not being reproduced by the same mechanism, two separate
sources again.

The only valid anology for what happens with a speaker reproducing a
complex waveform would be some other single entity that is capable of
reproducing the same complex waveform. Any suggestions?


** Lay off the weed.

The sound produced by the speaker happens because the speaker is driven
by a single complex waveform, thus there is a single source for the sound.
The sound that comes from a train whistle is generated by the whistle, and
the motion imparted to the whistle comes from the train's motion, two
separate sources. If you move the whistle back and forth in a manner
approximating that of a speaker cone, you still have two sources, the
whistle's sound and the mechanical vibration of the whistle, if you mount
the whistle on the speaker cone, you have two sources, that driving the cone
and that coming from the whistle. None of those approximates in any way, or
is a valid anology for a loudspeaker producing a complex waveform that comes
from only one source, the complex electrical waveform driving the speaker
motor. All the other anologies have two sources, one for the low frequency
motion and one for the high frequency sound, NOT a valid anology for what
happens when a speaker reproduced a complex waveform. If you don't get that,
then perhaps it is you who should "lay off the weed". You aren't going to
get it until you can differentiate that which comes from two or more
separate simple driving sources and that which comes from a single complex
driving source
BTW, I never said anything about a cone's motion being prodiuced by sound.
I said "a speaker reproducing a complex waveform".

"Porky"

The sound produced by the speaker happens because the speaker is driven
by a single complex waveform, thus there is a single source for the sound.
The sound that comes from a train whistle is generated by the whistle, and
the motion imparted to the whistle comes from the train's motion, two
separate sources.


** WRONG !!!

There is only one source of sound in both cases.

Case 1 = the cone.

Case 2 = the whistle.



If you move the whistle back and forth in a manner
approximating that of a speaker cone, you still have two sources, the
whistle's sound and the mechanical vibration of the whistle, if you mount
the whistle on the speaker cone, you have two sources, that driving the
cone
and that coming from the whistle.


** I told you to lay off that damn weed !!


None of those approximates in any way, or
is a valid anology for a loudspeaker producing a complex waveform that
comes
from only one source, the complex electrical waveform driving the speaker
motor.


** The SOURCE source of any sound is the vibrating object or air column.


All the other anologies have two sources, one for the low frequency
motion and one for the high frequency sound,


** Simply not relevant.


NOT a valid anology for what
happens when a speaker reproduced a complex waveform. If you don't get
that,
then perhaps it is you who should "lay off the weed".


** There is nothing rational anywhere in your posts to get.


You aren't going to
get it until you can differentiate that which comes from two or more
separate simple driving sources and that which comes from a single complex
driving source


** Totally false distinction.

It exists only in the words.


BTW, I never said anything about a cone's motion being prodiuced by
sound.
I said "a speaker reproducing a complex waveform".


** Quote:

" Even moving the whistle back and forth in approximation of a
moving speaker cone is not a valid anology, because the whistle's back
and forth motion is not generated by the sound coming from the whistle, as
it would be in a speaker reproducing a complex waveform. "


** Yes you did, then deceitfully snipped it.

Bet the weed made you do that......




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

"Porky" wrote in message

"Arny Krueger" wrote in message
news
"Bob Cain" wrote in message

Bob Cain wrote:



Arny Krueger wrote:


Sorry Bob, but I'm not buying.


How about this, then:

1) It is the bulk velocity, the flow of air, at the rest position
that propagates out as the velocity wave.

Frankly, over my head.

2) The bulk velocity at the rest position is the same as the
surface velocity of the piston.

Frankly, over my head.

And, finally:

3) In the frame of reference of the rest position of the
piston, no Doppler shift can be observed.

That seems wrong, because the following is right:

In the frame of reference of the piston, no Doppler shift can be
observed.

That's the listener riding the same train as the whistle.


It seems to me that the train/whistle anology is not a valid one for
this purpose, because the train's motion and the whistle's sound are
not being reproduced by the same source, as happens in a loudspeaker
producing a complex waveform.

It's just a matter of scale. The world is the equivalent of the chassis of
the speaker. The effective diaphragm of the whistel is the woofer cone.

If you make a recording of the train approaching and receeding from
your listening position and play it back, you will hear exactly the
same Doppler shift you heard when the train went by, and this can be
confirmed by measurement.

And, if the train travels in a really large sine wave, it's a lot like a
speaker.

Conversely, if you make a recording of the
whistle from the train and play it back on a speaker moving down the
tracks at the same velocity as the train, you will hear the same
doppler shift you heard from the passing train, even though there is
no shift in the actual recording.

Agreed..

The above logic actually has
little to do with Doppler distortion in a speaker, but the fact
remains that the train/whistle in not a valid anology!

Have it your way, if that's what you want. I'm not buying that there is a
substantial difference.

Making the
assumption that a speaker produces Doppler shift because a whistle on
a moving train does is a rationalization not based on the actual
physical facts.

False.

Even moving the whistle back and forth in
approximation of a moving speaker cone is not a valid anology,
because the whistle's back and forth motion is not generated by the
sound coming from the whistle, as it would be in a speaker
reproducing a complex waveform.

Let's presume that the whistle is actually a mechanical horn with a
diaphragm which of course undergoes the identical same Doppler shift as an
air horn or steam whistle. The diaphragm of this mechanical train horn
follows a similar path, different only in scale, from a woofer cone.

You're actually dealing with two
separate sources producing separate waveforms.

Doesn't matter because the diaphragm that actually makes the sound follows a
similar path.

Mounting the whistle
on the speaker cone still won't be a valid anology because the
waveforms are not being reproduced by the same mechanism, two
separate sources again.

This turns out to be an irrelevant distinction. What matters is the path of
the diaphragm, or its moral equivalent.

The only valid anology for what happens with
a speaker reproducing a complex waveform would be some other single
entity that is capable of reproducing the same complex waveform. Any
suggestions?

A train, car or a boat.

The sound produced by the speaker happens because the speaker is driven
None of those approximates in any way, or
is a valid anology for a loudspeaker producing a complex waveform that comes
from only one source, the complex electrical waveform driving the speaker
motor. All the other anologies have two sources, one for the low frequency
motion and one for the high frequency sound, NOT a valid anology for what
happens when a speaker reproduced a complex waveform.

What if we take this to the extremes with a thought experiment:

Picture the largest loudspeaker in the universe sitting outside
somewhere. It's so big that it has a maximal excursion of several
feet. Now picture a very low bass signal played on that speaker at
almost maximal volume. The speaker cone is vibrating
in-out-in-out-in-out.

Now add to that signal a small, high pitched, low amplitude waveform.
The two waveforms are added together so that it seems like the higher
pitched wave is "riding on top of" the bass wave. As far as our
super-excursion speaker is concerned, the location that's generating
the high pitched sound is moving forward and backward several feet.

If you still don't believe that this scenario validates the
train-whistle analogy, why not make the bass waveform move at the
speed of, oh say a train, and have the high pitched signal on top of
it be, oh say the sound of a whistle.

The scenario described in this thought experiment would *certainly*
produce doppler shift in the higher signals. If you made the bass
carrier sound low enough frequency and loud enough, you would even be
able to hear the weeeooohhweeeoooh modulation of the higher frequency
as the source of that sound (the surface of the speaker cone) is
moving towards and away from you. It follows reasonably that this also
happens with regular speakers, but to a lesser extent.

The question of whether it's a relevant, measurable, or hearable
distortion is a separate issue from whether it physically exists.

Forgive me if this has already been discussed to this point, I didn't
have time to read the entire thread.

Ken

"PenguiN"

What if we take this to the extremes with a thought experiment:

Picture the largest loudspeaker in the universe sitting outside
somewhere. It's so big that it has a maximal excursion of several
feet. Now picture a very low bass signal played on that speaker at
almost maximal volume. The speaker cone is vibrating
in-out-in-out-in-out.

Now add to that signal a small, high pitched, low amplitude waveform.
The two waveforms are added together so that it seems like the higher
pitched wave is "riding on top of" the bass wave. As far as our
super-excursion speaker is concerned, the location that's generating
the high pitched sound is moving forward and backward several feet.

If you still don't believe that this scenario validates the
train-whistle analogy, why not make the bass waveform move at the
speed of, oh say a train, and have the high pitched signal on top of
it be, oh say the sound of a whistle.

The scenario described in this thought experiment would *certainly*
produce doppler shift in the higher signals. If you made the bass
carrier sound low enough frequency and loud enough, you would even be
able to hear the weeeooohhweeeoooh modulation of the higher frequency
as the source of that sound (the surface of the speaker cone) is
moving towards and away from you. It follows reasonably that this also
happens with regular speakers, but to a lesser extent.

The question of whether it's a relevant, measurable, or hearable
distortion is a separate issue from whether it physically exists.

Forgive me if this has already been discussed to this point, I didn't
have time to read the entire thread.

Ken



** I reckon Ken must be an ambulatoy gum chewer.



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

ruffrecords writes:

PenguiN wrote:
The sound produced by the speaker happens because the speaker is driven
None of those approximates in any way, or
is a valid anology for a loudspeaker producing a complex waveform that comes
from only one source, the complex electrical waveform driving the speaker
motor. All the other anologies have two sources, one for the low frequency
motion and one for the high frequency sound, NOT a valid anology for what
happens when a speaker reproduced a complex waveform.

What if we take this to the extremes with a thought experiment:

Picture the largest loudspeaker in the universe sitting outside

somewhere. It's so big that it has a maximal excursion of several
feet. Now picture a very low bass signal played on that speaker at
almost maximal volume. The speaker cone is vibrating
in-out-in-out-in-out.
Now add to that signal a small, high pitched, low amplitude waveform.

The two waveforms are added together so that it seems like the higher
pitched wave is "riding on top of" the bass wave.


What gets added are the instantaneous pressures. The air pressure
produced is exactly the same as two separate speakers at the two
frequencies. There is no such thing as doppler distortion.

Consider this gedanken: Place a 4-inch speaker on the cone of a 14-foot
speaker. Now, the two speakers are fed different signals. Is there
Doppler? Yes. Use the one 14-foot speaker for both frequencies. Is there
Doppler? Left as an exercise for the student.

Granted, there will be differences, but the lack of doppler will not
be one of them. One of them will be the dispersion characterstics of
the high-frequency signal.

The difference between receiving two such summed signals electrically
versus acoustically is that one has the physical phenomenom of the
propagation of sound through the air in one case and not in the other.
Similarly, an electronic receiver may have other types of non-linear
distortion (e.g., clipping) depending on the circuit and parameters
that an acoustic receiver would not have. The two do not necessarily
have to agree with one another - there are different physical processes
that occur in each.

Get out a physics book and read about Doppler. The explanation of
how the observed wavelength changes when there is a relative velocity
between the source and observer should make you a believer that this
is precisely the scene in a speaker reproducing two frequencies.
--
Randy Yates
Sony Ericsson Mobile Communications
Research Triangle Park, NC, USA
, 919-472-1124

"ruffrecords" wrote in message


PenguiN wrote:

As far as our
super-excursion speaker is concerned, the location that's generating
the high pitched sound is moving forward and backward several feet.

No it isn't. This is the flaw in all the doppler distortion
arguments.

If all the explanations for Doppler distortion are wrong, where does all of
the FM we measure come from? Why does it correlate well with the *incorrect*
theoretical predictions?

PenguiN wrote:
The sound produced by the speaker happens because the speaker is driven
None of those approximates in any way, or
is a valid anology for a loudspeaker producing a complex waveform that comes
from only one source, the complex electrical waveform driving the speaker
motor. All the other anologies have two sources, one for the low frequency
motion and one for the high frequency sound, NOT a valid anology for what
happens when a speaker reproduced a complex waveform.


What if we take this to the extremes with a thought experiment:

Picture the largest loudspeaker in the universe sitting outside
somewhere. It's so big that it has a maximal excursion of several
feet. Now picture a very low bass signal played on that speaker at
almost maximal volume. The speaker cone is vibrating
in-out-in-out-in-out.

Now add to that signal a small, high pitched, low amplitude waveform.
The two waveforms are added together so that it seems like the higher
pitched wave is "riding on top of" the bass wave.

What gets added are the instantaneous pressures. The air pressure
produced is exactly the same as two separate speakers at the two
frequencies. There is no such thing as doppler distortion.

Ian


As far as our
super-excursion speaker is concerned, the location that's generating
the high pitched sound is moving forward and backward several feet.

No it isn't. This is the flaw in all the doppler distortion arguments.

Ian

In alt.music.home-studio,rec.audio.tech,rec.audio.pro,
(PenguiN) wrote:

The sound produced by the speaker happens because the speaker is driven
None of those approximates in any way, or
is a valid anology for a loudspeaker producing a complex waveform that comes
from only one source, the complex electrical waveform driving the speaker
motor. All the other anologies have two sources, one for the low frequency
motion and one for the high frequency sound, NOT a valid anology for what
happens when a speaker reproduced a complex waveform.

What if we take this to the extremes with a thought experiment:

Picture the largest loudspeaker in the universe sitting outside
somewhere. It's so big that it has a maximal excursion of several
feet. Now picture a very low bass signal played on that speaker at
almost maximal volume. The speaker cone is vibrating
in-out-in-out-in-out.

Now add to that signal a small, high pitched, low amplitude waveform.
The two waveforms are added together so that it seems like the higher
pitched wave is "riding on top of" the bass wave. As far as our
super-excursion speaker is concerned, the location that's generating
the high pitched sound is moving forward and backward several feet.

If you still don't believe that this scenario validates the
train-whistle analogy, why not make the bass waveform move at the
speed of, oh say a train, and have the high pitched signal on top of
it be, oh say the sound of a whistle.

The scenario described in this thought experiment would *certainly*
produce doppler shift in the higher signals. If you made the bass
carrier sound low enough frequency and loud enough, you would even be
able to hear the weeeooohhweeeoooh modulation of the higher frequency
as the source of that sound (the surface of the speaker cone) is
moving towards and away from you. It follows reasonably that this also
happens with regular speakers, but to a lesser extent.

The question of whether it's a relevant, measurable, or hearable
distortion is a separate issue from whether it physically exists.

Forgive me if this has already been discussed to this point, I didn't
have time to read the entire thread.

I made what I considered to be a similar 'extreme' post, but your
woofer cone moves an order or two of magnitide greater distance than
mine does. So I commend your post, it needed to be said.

As far as not having time to read the whole thread, I've been
participating, so it's a sad commentary on where I'm spending my time.

Someone should have just said at the start "Bob Cain (and a few
others here) is in denial about the existence of Doppler effect in
speakers" and I wouldn't have tried so hard...

Ken

-----
http://mindspring.com/~benbradley

On Sun, 15 Aug 2004 22:56:47 -0700, Bob Cain
wrote:



Porky wrote:

At that velocity, it
simply doesn't have time to dopple!:-)

That's cute. Wrong, but nonetheless cute. :-)

It WILL cause a phase shift, and I have no doubt you can set this
up and see a practical demonstration of this on an oscilloscope, and
phase shift, no matter how slow, IS equivalent to a frequency change.

It dopples, just as surely at the Earth moves.



Bob

-----
http://mindspring.com/~benbradley

Arny Krueger wrote:

"Bob Cain" wrote in message


Porky wrote:


True, but who's going to hear doppler shift at that level, even if
it does exist?:-)

To me it doesn't matter whether we can hear it or not. As
of now there is no predictive theory that yields
quantitative results we could test with experiment anyway.
I want to know whether or not it is a real phenomenon at all.


How are you doing with the 60KB or so of AES paper references that I posted
in RAP?

Not well without access to the papers. If you can point me
to at least one of them that solves the problem analytically
to yield a general mathematical description I'll purhase it.


Bob
--

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

A. Einstein

Arny Krueger wrote:

"Bob Cain" wrote in message


Bob Cain wrote:



Arny Krueger wrote:



Sorry Bob, but I'm not buying.


How about this, then:

1) It is the bulk velocity, the flow of air, at the rest position
that propagates out as the velocity wave.


Frankly, over my head.

That's hard to believe. What part of it evades you?



2) The bulk velocity at the rest position is the same as the surface
velocity of the piston.


Frankly, over my head.

Same.



And, finally:


3) In the frame of reference of the rest position of the
piston, no Doppler shift can be observed.


That seems wrong, because the following is right:

In the frame of reference of the piston, no Doppler shift can be observed.

If you are in the frame of reference of the piston, you're
going to get shanken _all_ to hell. :-)


Bob
--

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

A. Einstein

"Bob Cain" wrote in message

Arny Krueger wrote:

"Bob Cain" wrote in message


3) In the frame of reference of the rest position of the
piston, no Doppler shift can be observed.

That seems wrong, because the following is right:

In the frame of reference of the piston, no Doppler shift can be
observed.

If you are in the frame of reference of the piston, you're
going to get shanken _all_ to hell. :-)

Agreed.

Hey, you think getting zero Doppler is always painless? ;-)

Randy Yates wrote:
ruffrecords writes:


PenguiN wrote:

The sound produced by the speaker happens because the speaker is driven
None of those approximates in any way, or
is a valid anology for a loudspeaker producing a complex waveform that comes

from only one source, the complex electrical waveform driving the speaker

motor. All the other anologies have two sources, one for the low frequency
motion and one for the high frequency sound, NOT a valid anology for what
happens when a speaker reproduced a complex waveform.

What if we take this to the extremes with a thought experiment:

Picture the largest loudspeaker in the universe sitting outside

somewhere. It's so big that it has a maximal excursion of several
feet. Now picture a very low bass signal played on that speaker at
almost maximal volume. The speaker cone is vibrating
in-out-in-out-in-out.
Now add to that signal a small, high pitched, low amplitude waveform.

The two waveforms are added together so that it seems like the higher
pitched wave is "riding on top of" the bass wave.


What gets added are the instantaneous pressures. The air pressure
produced is exactly the same as two separate speakers at the two
frequencies. There is no such thing as doppler distortion.


Consider this gedanken: Place a 4-inch speaker on the cone of a 14-foot
speaker. Now, the two speakers are fed different signals.

Consider this. place a 14ft speaker next to a 4inch speaker and feed
them different signals. Is there Doppler? No


The difference between receiving two such summed signals electrically
versus acoustically is that one has the physical phenomenom of the
propagation of sound through the air in one case and not in the other.

I did not mention electrical adding of the signals.



Get out a physics book and read about Doppler. The explanation of
how the observed wavelength changes when there is a relative velocity
between the source and observer should make you a believer that this
is precisely the scene in a speaker reproducing two frequencies.

get an electrical test book and read about linear superpostion.

Ian

ruffrecords writes:

Randy Yates wrote:
ruffrecords writes:


PenguiN wrote:

The sound produced by the speaker happens because the speaker is driven
None of those approximates in any way, or
is a valid anology for a loudspeaker producing a complex waveform that comes

from only one source, the complex electrical waveform driving the speaker

motor. All the other anologies have two sources, one for the low frequency
motion and one for the high frequency sound, NOT a valid anology for what
happens when a speaker reproduced a complex waveform.

What if we take this to the extremes with a thought experiment:

Picture the largest loudspeaker in the universe sitting outside

somewhere. It's so big that it has a maximal excursion of several
feet. Now picture a very low bass signal played on that speaker at
almost maximal volume. The speaker cone is vibrating
in-out-in-out-in-out.
Now add to that signal a small, high pitched, low amplitude waveform.

The two waveforms are added together so that it seems like the higher
pitched wave is "riding on top of" the bass wave.


What gets added are the instantaneous pressures. The air pressure
produced is exactly the same as two separate speakers at the two
frequencies. There is no such thing as doppler distortion.
Consider this gedanken: Place a 4-inch speaker on the cone of a
14-foot

speaker. Now, the two speakers are fed different signals.

Consider this. place a 14ft speaker next to a 4inch speaker and feed
them different signals. Is there Doppler? No

Hey man, stay stupid - see if I give a ****.

The difference between receiving two such summed signals electrically

versus acoustically is that one has the physical phenomenom of the
propagation of sound through the air in one case and not in the other.

I did not mention electrical adding of the signals.


Get out a physics book and read about Doppler. The explanation of

how the observed wavelength changes when there is a relative velocity
between the source and observer should make you a believer that this
is precisely the scene in a speaker reproducing two frequencies.


get an electrical test book and read about linear superpostion.

You mean a text on linear system theory and/or basic circuit analysis?
Like Oppenheim and Willsky's "Signals and Systems"? Or Sedra and
Smith's "Microelectronic Circuits"? Or how about the old standard,
Boylestad's "Circuit Analysis"? I've read those books over the course
of 20 years and two degrees in electrical engineering.

I've also read about the migratory behavior of sperm whales, but
neither one have anything to do with the Doppler effect in
speakers. So forget this argument and go buy another eighth of
sensamilla at your local pot store.
--
Randy Yates
Sony Ericsson Mobile Communications
Research Triangle Park, NC, USA
, 919-472-1124

Arny Krueger wrote:
"ruffrecords" wrote in message



PenguiN wrote:


As far as our

super-excursion speaker is concerned, the location that's generating
the high pitched sound is moving forward and backward several feet.


No it isn't. This is the flaw in all the doppler distortion
arguments.


If all the explanations for Doppler distortion are wrong, where does all of
the FM we measure come from? Why does it correlate well with the *incorrect*
theoretical predictions?



To produce FM there needs to be a non-linearity. If you detect FM there
is a good chance a non-linearity exists. But it is not due to the
doppler effect.

Ian

ruffrecords wrote:

To produce FM there needs to be a non-linearity. If you detect FM there
is a good chance a non-linearity exists. But it is not due to the
doppler effect.

Exactly, and until an experiment is done which eliminates
all other driver non-linearities an experiment hasn't been done.


Bob
--

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

A. Einstein

Randy Yates wrote:
ruffrecords writes:


Randy Yates wrote:

ruffrecords writes:


PenguiN wrote:


The sound produced by the speaker happens because the speaker is driven
None of those approximates in any way, or
is a valid anology for a loudspeaker producing a complex waveform that comes

from only one source, the complex electrical waveform driving the speaker


motor. All the other anologies have two sources, one for the low frequency
motion and one for the high frequency sound, NOT a valid anology for what
happens when a speaker reproduced a complex waveform.

What if we take this to the extremes with a thought experiment:

Picture the largest loudspeaker in the universe sitting outside

somewhere. It's so big that it has a maximal excursion of several
feet. Now picture a very low bass signal played on that speaker at
almost maximal volume. The speaker cone is vibrating
in-out-in-out-in-out.
Now add to that signal a small, high pitched, low amplitude waveform.

The two waveforms are added together so that it seems like the higher
pitched wave is "riding on top of" the bass wave.


What gets added are the instantaneous pressures. The air pressure
produced is exactly the same as two separate speakers at the two
frequencies. There is no such thing as doppler distortion.

Consider this gedanken: Place a 4-inch speaker on the cone of a
14-foot

speaker. Now, the two speakers are fed different signals.

Consider this. place a 14ft speaker next to a 4inch speaker and feed
them different signals. Is there Doppler? No



Hey man, stay stupid - see if I give a ****.

Nothing stupid about it. If both systems are linear then they will work
in an identical manner.

Ian

"ruffrecords" wrote in message

Arny Krueger wrote:
"ruffrecords" wrote in message



PenguiN wrote:


As far as our

super-excursion speaker is concerned, the location that's
generating the high pitched sound is moving forward and backward
several feet.


No it isn't. This is the flaw in all the doppler distortion
arguments.


If all the explanations for Doppler distortion are wrong, where does
all of the FM we measure come from? Why does it correlate well with
the *incorrect* theoretical predictions?



To produce FM there needs to be a non-linearity.

Not really. A nonlinearity produces AM.

FM is exactly what Doppler distortion produces.

If you detect FM there is a good chance a non-linearity exists.

If you do the math, nonlinearities can't produce FM distoriton. You need
something that operates in the time domain, not the amplitude domain.

But it is not due to the Doppler effect.

ruffrecords writes:
If both systems are linear then they will
work in an identical manner.

That statement is absolutely correct, just as "If I am pregnant,
then I am a female." is absolutely correct.
--
% Randy Yates % "Maybe one day I'll feel her cold embrace,
%% Fuquay-Varina, NC % and kiss her interface,
%%% 919-577-9882 % til then, I'll leave her alone."
%%%% % 'Yours Truly, 2095', *Time*, ELO
http://home.earthlink.net/~yatescr

Bob Cain writes:

ruffrecords wrote:

To produce FM there needs to be a non-linearity. If you detect FM
there is a good chance a non-linearity exists. But it is not due to
the doppler effect.

Exactly,

Not. Get a clue, people. Doppler is a *PHYSICAL PHENOMENOM* that
WILL happen whether or not you decide it can WHENEVER a sound wave
source and observer are moving relative to each other. Period. This
isn't open for debate.
--
% Randy Yates % "Though you ride on the wheels of tomorrow,
%% Fuquay-Varina, NC % you still wander the fields of your
%%% 919-577-9882 % sorrow."
%%%% % '21st Century Man', *Time*, ELO
http://home.earthlink.net/~yatescr

"ruffrecords"

What gets added are the instantaneous pressures. The air pressure
produced is exactly the same as two separate speakers at the two
frequencies. There is no such thing as doppler distortion.

Ian



** Ian is another who cannot walk and chew gum at the same time.





.......... Phil

"Phil Allison" wrote in message
...

"Porky"

The sound produced by the speaker happens because the speaker is
driven
by a single complex waveform, thus there is a single source for the
sound.
The sound that comes from a train whistle is generated by the whistle,
and
the motion imparted to the whistle comes from the train's motion, two
separate sources.


** WRONG !!!

There is only one source of sound in both cases.

Case 1 = the cone.

Case 2 = the whistle.



If you move the whistle back and forth in a manner
approximating that of a speaker cone, you still have two sources, the
whistle's sound and the mechanical vibration of the whistle, if you
mount
the whistle on the speaker cone, you have two sources, that driving the
cone
and that coming from the whistle.


** I told you to lay off that damn weed !!


None of those approximates in any way, or
is a valid anology for a loudspeaker producing a complex waveform that
comes
from only one source, the complex electrical waveform driving the
speaker
motor.


** The SOURCE source of any sound is the vibrating object or air column.


All the other anologies have two sources, one for the low frequency
motion and one for the high frequency sound,


** Simply not relevant.


NOT a valid anology for what
happens when a speaker reproduced a complex waveform. If you don't get
that,
then perhaps it is you who should "lay off the weed".


** There is nothing rational anywhere in your posts to get.


You aren't going to
get it until you can differentiate that which comes from two or more
separate simple driving sources and that which comes from a single
complex
driving source


** Totally false distinction.

It exists only in the words.


BTW, I never said anything about a cone's motion being prodiuced by
sound.
I said "a speaker reproducing a complex waveform".


** Quote:

" Even moving the whistle back and forth in approximation of a
moving speaker cone is not a valid anology, because the whistle's back
and forth motion is not generated by the sound coming from the whistle,
as
it would be in a speaker reproducing a complex waveform. "


** Yes you did, then deceitfully snipped it.

In the first place, I don't go drugs of any kind, including weed and
alcohol, and in the second place if you don't see the difference between
providing all forms of motion involved (whether they produce sound or not)
with one complex source, and providing the different forms of motion
(whether they produce sound or not) with multiple simple sources, then any
conclusion you may come to is going to be fundamentally flawed, and all your
flippant answers aren't going to change that.

"PenguiN" wrote in message
om...
The sound produced by the speaker happens because the speaker is driven
None of those approximates in any way, or
is a valid anology for a loudspeaker producing a complex waveform that
comes
from only one source, the complex electrical waveform driving the
speaker
motor. All the other anologies have two sources, one for the low
frequency
motion and one for the high frequency sound, NOT a valid anology for
what
happens when a speaker reproduced a complex waveform.

What if we take this to the extremes with a thought experiment:

Picture the largest loudspeaker in the universe sitting outside
somewhere. It's so big that it has a maximal excursion of several
feet. Now picture a very low bass signal played on that speaker at
almost maximal volume. The speaker cone is vibrating
in-out-in-out-in-out.

Now add to that signal a small, high pitched, low amplitude waveform.
The two waveforms are added together so that it seems like the higher
pitched wave is "riding on top of" the bass wave. As far as our
super-excursion speaker is concerned, the location that's generating
the high pitched sound is moving forward and backward several feet.

Fundamental flaw in the logic, the higher pitched signal is not "riding on"
the lower pitched signal, they are combined to produce a complex waveform
driving the speaker.

If you still don't believe that this scenario validates the
train-whistle analogy, why not make the bass waveform move at the
speed of, oh say a train, and have the high pitched signal on top of
it be, oh say the sound of a whistle.

Doesn't apply, the train and whistle are supplied by two separate sources of
energy.

The scenario described in this thought experiment would *certainly*
produce doppler shift in the higher signals. If you made the bass
carrier sound low enough frequency and loud enough, you would even be
able to hear the weeeooohhweeeoooh modulation of the higher frequency
as the source of that sound (the surface of the speaker cone) is
moving towards and away from you. It follows reasonably that this also
happens with regular speakers, but to a lesser extent.

Once again, comparing two separate sources of motion (the train and the
whistle) provided by two separate sources of energy, to one complex motion
source provided by one single complex source of energy (the signal driving
the speaker motor) is comparing apples to oranges.

The question of whether it's a relevant, measurable, or hearable
distortion is a separate issue from whether it physically exists.

Agreed, but in order to reach any valid conclusions, one must stop comparing
apples to oranges!

"Porky"
"Phil Allison"


** Yes you did, then deceitfully snipped it.

In the first place, I don't go drugs of any kind, including weed and
alcohol, and in the second place if you don't see the difference between
providing all forms of motion involved (whether they produce sound or not)
with one complex source, and providing the different forms of motion
(whether they produce sound or not) with multiple simple sources, then any
conclusion you may come to is going to be fundamentally flawed, and all
your
flippant answers aren't going to change that.



** This little piggy cannot trot and chew gum at the same time.




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

"Porky"


Agreed, but in order to reach any valid conclusions, one must stop
comparing
apples to oranges!




** This litle piggy cannot trot and chew rotten fruit at the same time.




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

"Randy Yates" wrote in message
...
Bob Cain writes:

ruffrecords wrote:

To produce FM there needs to be a non-linearity. If you detect FM
there is a good chance a non-linearity exists. But it is not due to
the doppler effect.

Exactly,

Not. Get a clue, people. Doppler is a *PHYSICAL PHENOMENOM* that
WILL happen whether or not you decide it can WHENEVER a sound wave
source and observer are moving relative to each other. Period. This
isn't open for debate.

This whole argument is based on the wrong assumption that the high
frequency source is "riding on" the low frequency source like a whistle on a
train. It is NOT! Both sounds are being produced simultaneously by the
complex electrical waveform driving the speaker cone which moves in
accordance. Assuming that the speaker is being driven within its linear
limits, the cone's motion accurately follows the driving signal, and it is a
linear system.
Forget the train/whistle anology, it is not an accurate representation for
what goes on with a speaker, period!

"Phil Allison" wrote in message
...
In the first place, I don't go drugs of any kind, including weed and
alcohol, and in the second place if you don't see the difference between
providing all forms of motion involved (whether they produce sound or
not)
with one complex source, and providing the different forms of motion
(whether they produce sound or not) with multiple simple sources, then
any
conclusion you may come to is going to be fundamentally flawed, and all
your
flippant answers aren't going to change that.



** This little piggy cannot trot and chew gum at the same time.

Are you kidding? I can drive a racecar while chewing gum and
simultaneously contemplating the possibility that a speaker can generate
Doppler distortion while producing multiple tones when driven by a single
complex waveform, and at the same calculating the probibility (approx
83.762%) that you are the one who is smoking weed.:-)

"Phil Allison" wrote in message
...

"Porky"


Agreed, but in order to reach any valid conclusions, one must stop
comparing
apples to oranges!




** This litle piggy cannot trot and chew rotten fruit at the same time.


Ah, yes, but Phil can, in fact, he does it all the time. Unfortunately the
rotten fruit has fermented and contains a high level of alcohol, which has
severely unbalanced Phil's mental process.:-)

"Porky" writes:

"Randy Yates" wrote in message
...
Bob Cain writes:

ruffrecords wrote:

To produce FM there needs to be a non-linearity. If you detect FM
there is a good chance a non-linearity exists. But it is not due to
the doppler effect.

Exactly,

Not. Get a clue, people. Doppler is a *PHYSICAL PHENOMENOM* that
WILL happen whether or not you decide it can WHENEVER a sound wave
source and observer are moving relative to each other. Period. This
isn't open for debate.

This whole argument is based on the wrong assumption that the high
frequency source is "riding on" the low frequency source like a whistle on a
train. It is NOT!

Oh, but it is. That is precisely what is happening.

Both sounds are being produced simultaneously by the
complex electrical waveform driving the speaker cone which moves in
accordance.

True, and how does that refute that there is no Doppler? Before it
ever gets to a speaker, such an electrical signal will have the
characteristic of the high frequency wave "riding" on top of
the low frequency wave. You will see it on a scope. Input that to
a speaker and you will see precisely the same thing if you observed
a plot of speaker cone displacement versus time.

Assuming that the speaker is being driven within its linear
limits, the cone's motion accurately follows the driving signal,

True.

and it is a
linear system.

FALSE! Well, at least if you define "it" to be the entire composite system
from the speaker's electrical input to the acoustic receiver's input. In
that case, it ain't linear. That's the whole point. The physics of what
happens between the speaker cone and the acoustic observer are such that
Doppler will take effect. Now how *much* Dopper is another question, but
the effect will be there for sure, just as two masses will experience an attraction
based on the inverse square law (m1*m2/r^2).

Forget the train/whistle anology, it is not an accurate representation for
what goes on with a speaker, period!

Proof by assertion?
--
% Randy Yates % "Ticket to the moon, flight leaves here today
%% Fuquay-Varina, NC % from Satellite 2"
%%% 919-577-9882 % 'Ticket To The Moon'
%%%% % *Time*, Electric Light Orchestra
http://home.earthlink.net/~yatescr

On Mon, 16 Aug 2004 21:57:16 -0500, "Porky" wrote:


"PenguiN" wrote in message
. com...

If you still don't believe that this scenario validates the
train-whistle analogy, why not make the bass waveform move at the
speed of, oh say a train, and have the high pitched signal on top of
it be, oh say the sound of a whistle.

Doesn't apply, the train and whistle are supplied by two separate sources of
energy.

Have two amplifiers, one for the low frequency connected to the
speaker through an inductor, another amp outputting the high frequency
connected to the speaker through a capacitor. Thus the low and the
high are supplied by two separate sources of energy.

Actually, isn't the train whistle powered by steam from the same
boiler that powers the wheels, moving the train? What's up with that?

But seriously, for Bob and other anti-doppler-distortion folks, how
does cone-and-frame movement cause doppler while cone movement only
does not? What is it about the frame that causes doppler?

If you put the speaker on a shaker table, run 1kHz and 50 Hz
through the speaker, move the shaker table at 50 Hz opposite the phase
to the speaker so the cone only moves at the 1kHz rate with respect to
the air, will it generate doppler distorion? According to my
understanding of Bob's position, it should.
-----
http://mindspring.com/~benbradley

Porky wrote:

Are you kidding? I can drive a racecar while chewing gum and
simultaneously contemplating the possibility that a speaker can generate
Doppler distortion while producing multiple tones when driven by a single
complex waveform, and at the same calculating the probibility (approx
83.762%) that you are the one who is smoking weed.:-)

ROTFLOL! :-)


Bob
--

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

A. Einstein

ruffrecords wrote:

super-excursion speaker is concerned, the location that's generating
the high pitched sound is moving forward and backward several feet.


No it isn't. This is the flaw in all the doppler distortion arguments.

What he said.


Bob
--

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

A. Einstein

ruffrecords wrote:

Nothing stupid about it. If both systems are linear then they will work
in an identical manner.

What he said.


Bob
--

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

A. Einstein

Arny Krueger wrote:

If all the explanations for Doppler distortion are wrong, where does all of
the FM we measure come from? Why does it correlate well with the *incorrect*
theoretical predictions?

What theoretical prediction might that be? I've yet to see
a theory for "Doppler distortion" that predicts. Odd, that.


Bob
--

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

A. Einstein

Randy Yates wrote:

Not. Get a clue, people. Doppler is a *PHYSICAL PHENOMENOM* that
WILL happen whether or not you decide it can WHENEVER a sound wave
source and observer are moving relative to each other. Period. This
isn't open for debate.

Randy has spoken. Without one shread of a predictive
theory. Odd, that.


Bob
--

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

A. Einstein

Porky wrote:


This whole argument is based on the wrong assumption that the high
frequency source is "riding on" the low frequency source like a whistle on a
train. It is NOT! Both sounds are being produced simultaneously by the
complex electrical waveform driving the speaker cone which moves in
accordance. Assuming that the speaker is being driven within its linear
limits, the cone's motion accurately follows the driving signal, and it is a
linear system.
Forget the train/whistle anology, it is not an accurate representation for
what goes on with a speaker, period!

What he said. Is this the same Porky that I've argued with
about _so_ many things?


Bob
--

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

A. Einstein