"Porky" wrote in message ...

...And methinks The Ghost has protoplasmic porcine paskat for brains.
(I had to resort to Finnish to keep the alliteration going:-))
BTW, no point in replying to this because you've been *plonked*

Like I really give a rat's ass, you moron. Keep posting and join Bob
Cain in advertising your technical ignorance to the world.

"Here's another way of looking at it, putting a sound wave through a hole
in the wall can't produce Doppler shift, no matter how many tones are in the
waveform, and a speaker is effectively an artificial hole in the wall, in
that the effective sound source isn't the speaker any more than it is the
hole in the wall. Does anyone here think that if you stretched a thin
diaphragm over a hole in a soundproof wall and had a band playing behind it,
the diaphragm would cause Doppler Distortion? The speaker, provided it isn't
exceeding its linear limits, is effectively exactly the same thing for all
practical purposes. Instead of being driven by the sound source in the other
room, it's driven by the electrical equivalent of the sound source in the
other room. Can any of you provide an explanation of how an acoustic wave
driving a diaphragm and passing the soundwave
through it is in any way different than the diaphragm being driven by a
motor being supplied with the exact electrical analog of that acoustic wave?
And by that I mean that the difference will be such that the electrically
driven one will produce Doppler distortion while the acoustically driven one
doesn't."
It seems to me that it boils down to the above situation, if the diaphragm
covering the hole in the wall driven directly by the acoustic wave in the
other room doesn't produce Doppler shift, then the diaphragm being driven by
the exactly equivalent electrical wave won't either. Since the diaphragm
over the hole is moving exactly like the acoustic wave coming through the
hole, I don't see how any form of Doppler shift could be introduced, as
obviously, the hole itself won't introduce Doppler shift. Note, I'm
referring only to Doppler shift, not the lowpass effect of the hole, the
inertia of the diaphragms, etc, which may affect the sound, but will have
absolutely nothing to do with Doppler shift.


This is a very interesting thought experiment! But I believe I have
the answer.

A diaphragm's movement caused by a sound wave on the other side of the
wall is *not* the same movement as a speaker's produced by the same
sound in electrical wave form.

Let's set up this situation:
-- Room with sound sources - Diaphragm over hole - air on other
side
-VS-
-- electrical wave exactly replicating the waveform from those sound
sources - speaker cone - air in front of speaker.

First, what happens in the room:

Let's start out with an incredibly low frequency, loud source in the
room. We'll assume that this causes a waveform in the air with huge
pressure gradients that causes the diaphram to move in-out-in-out
relatively slowly with a very large amplitude.

While this is happening, we then start up a second source in the room,
which is high frequency, and lower amplitude. Assuming the air is 100%
linear, the two waveforms will add together perfectly.

However, when the higher frequency waveform (series of pressure
changes in the air) reaches the diaphragm, the diaphram is in *motion*
due to the low frequency source. This motion is relative to the high
frequency source, and therefore, instead of adding a perfect
representation of the high frequency waveform on top of the
diaphragm's movements, a *DOPPLER SHIFTED VERSION* of that high
frequency waveform appears on the diaphragm!

In other words, not only do speakers exhibit doppler distortion, but
microphone diaphragms would, as well! (if one does, then the other
should, too. This only makes sense). We generally don't care about it
with microphones, because the diaphragms move so slightly that it's
basically not there at all.

But in this thought experiment, it's there!

Now, on the other side of the wall, the diaphragm is vibrating a
doppler-distorted version of the original sounds. On this side, it
effectively acts like a speaker, and the waveform it's vibrating at
(the doppler distorted version of the original) is *again* doppler
distorted when going into the next room.

Now, I haven't done the math out on this, but I would suspect that any
doppler effects caused by the diaphragm "picking up" the waveform
would be *EXACTLY CANCELED OUT* by the doppler effects of the
diaphragm vibrating the air in the next room.

Net result: No doppler distortion through a diaphragm over a hole in
the wall!


Now, the speaker, on the other hand, exhibits the doppler distortion
going from speaker-air, with no "compensating" distortion on the
recording end, and therefore still exhibits doppler distortion. Well,
unless the microphone used the exact same transducer as the speaker to
record, and it had the same excursion -- then the doppler effect of
the microphone would cancel out the doppler effect of the speaker, and
the result would be an un-doppler-distorted recreation of the original
acoustic sound. HOWEVER, the resultant sound is *still* a doppler
distorted version of the *electrical* waveform, technically.

Ken

if this were the case then Doppler shift would be a part of the natural
order of things musical, and Doppler shift could thus be entirely
disregarded as a source of "distortion", period!
I think this should pretty much drive the final nail in the Doppler
distortion issue's coffin, because if speakers introduce Doppler shift then
so does everything else which vibrates to produce sound. I still don't think
Doppler shift is introduced by speakers opperating under normal conditions,
but if it is, it's a part of the natural order and not distortion at all!:-)

The difference is that "doppler distortion" is a measurement that
compares an *ideal* waveform (ie, what's on the wire) with the
*realized* waveform (what's in the air). Distortion that isn't present
in the wire but is in the air is undesirable.

Yes, one part of the sound of a vibrating string is caused by a
"doppler effect" of the fact that the string is moving through the
air. (This may be inaudible, but that's besides the point).

However, that's part of the sound of the string, and therefore it's
desireable. If you were to then put it through a speaker that added
*additional* doppler (or whatever) distortion, then that would *not*
be desireable (if re-creating the recorded sound was your goal).

So no, this doesn't nail any coffins. Sorry.

It's like saying "electric guitar amps have harmonic distortion --
therefore it shouldn't matter if my studio's speakers also cause
harmonic distortion because this is part of the sound of the amp
anyway!" -- yeah, try to put that by any audio engineer

Ken

The Ghost wrote:

"Porky" wrote in message ...

...And methinks The Ghost has protoplasmic porcine paskat for brains.
(I had to resort to Finnish to keep the alliteration going:-))
BTW, no point in replying to this because you've been *plonked*


Like I really give a rat's ass, you moron. Keep posting and join Bob
Cain in advertising your technical ignorance to the world.

You keep posting this kind of mindless, pathological drivel
when you offer absolutely nothing to indicate an iota of
technical acumen on your own part. Wow, you possibly set up
an experiment to show that somehow, somewhere in the process
a phase modulation occurs, but so what? That's not at all
in dispute.

How's about, just for kicks, giving us a derivation of the
theory you know and love with all axioms displayed for
critique, one that can predict what experiment will show?
You pretend to be the great theorist but have offered no
theory whatsoever.

As I've admitted I have no such detailed theory yet for the
principle I favor either, but then again I don't claim to be
a great theorist, just an independant thinker with a knack
for poking holes in shiboleths.


Bob
--

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

A. Einstein

"PenguiN" wrote in message
om...
if this were the case then Doppler shift would be a part of the natural
order of things musical, and Doppler shift could thus be entirely
disregarded as a source of "distortion", period!
I think this should pretty much drive the final nail in the Doppler
distortion issue's coffin, because if speakers introduce Doppler shift
then
so does everything else which vibrates to produce sound. I still don't
think
Doppler shift is introduced by speakers opperating under normal
conditions,
but if it is, it's a part of the natural order and not distortion at
all!:-)

The difference is that "doppler distortion" is a measurement that
compares an *ideal* waveform (ie, what's on the wire) with the
*realized* waveform (what's in the air). Distortion that isn't present
in the wire but is in the air is undesirable.

Yes, one part of the sound of a vibrating string is caused by a
"doppler effect" of the fact that the string is moving through the
air. (This may be inaudible, but that's besides the point).

However, that's part of the sound of the string, and therefore it's
desireable. If you were to then put it through a speaker that added
*additional* doppler (or whatever) distortion, then that would *not*
be desireable (if re-creating the recorded sound was your goal).

So no, this doesn't nail any coffins. Sorry.

It's like saying "electric guitar amps have harmonic distortion --
therefore it shouldn't matter if my studio's speakers also cause
harmonic distortion because this is part of the sound of the amp
anyway!" -- yeah, try to put that by any audio engineer

What I said was that if everything that vibrates when producing complex
sound produces Doppler shift, then our hearing mechanism has the built in
ability to compensate for it. This doesn't affect my position, which is that
I feel that any diaphragm which is driven by a single complex waveform
produces a coherent complex soundwave which isn't subject to Doppler shift
(the hole in the wall model), as opposed to compound diaphragms being driven
by separate sources which actually produce two separate waves which are
summed in the air, and being that the summation process doesn't occur
instantaneously, there is oppurtunity for Doppler shift to occur before or
during the summation process (the train/whistle model).

"Scott Dorsey" wrote in message
...
Jim Carr wrote:

If you accept Doppler "distortion" as described by others, then
instruments
producing multiple tones has the problem. Hit two keys on the piano and
the
wood vibrates for both sounds.

Yes, absolutely! There are all _kinds_ of weird modulation effects going
on
between notes on pianos. That is why pianos are so difficult to simulate
believably.

On the whole, though, the sympathetic vibration effects in a piano are
going to swamp everything else... and some of them are not even harmonic!

Very true, but those vibrations are unrelated to Doppler shift and would
overwhelm it if it did occur, :-)

"PenguiN" wrote in message
om...
"Here's another way of looking at it, putting a sound wave through a
hole
in the wall can't produce Doppler shift, no matter how many tones are in
the
waveform, and a speaker is effectively an artificial hole in the wall,
in
that the effective sound source isn't the speaker any more than it is
the
hole in the wall. Does anyone here think that if you stretched a thin
diaphragm over a hole in a soundproof wall and had a band playing behind
it,
the diaphragm would cause Doppler Distortion? The speaker, provided it
isn't
exceeding its linear limits, is effectively exactly the same thing for
all
practical purposes. Instead of being driven by the sound source in the
other
room, it's driven by the electrical equivalent of the sound source in
the
other room. Can any of you provide an explanation of how an acoustic
wave
driving a diaphragm and passing the soundwave
through it is in any way different than the diaphragm being driven by a
motor being supplied with the exact electrical analog of that acoustic
wave?
And by that I mean that the difference will be such that the
electrically
driven one will produce Doppler distortion while the acoustically driven
one
doesn't."
It seems to me that it boils down to the above situation, if the
diaphragm
covering the hole in the wall driven directly by the acoustic wave in
the
other room doesn't produce Doppler shift, then the diaphragm being
driven by
the exactly equivalent electrical wave won't either. Since the diaphragm
over the hole is moving exactly like the acoustic wave coming through
the
hole, I don't see how any form of Doppler shift could be introduced, as
obviously, the hole itself won't introduce Doppler shift. Note, I'm
referring only to Doppler shift, not the lowpass effect of the hole, the
inertia of the diaphragms, etc, which may affect the sound, but will
have
absolutely nothing to do with Doppler shift.


This is a very interesting thought experiment! But I believe I have
the answer.

A diaphragm's movement caused by a sound wave on the other side of the
wall is *not* the same movement as a speaker's produced by the same
sound in electrical wave form.

Let's set up this situation:
-- Room with sound sources - Diaphragm over hole - air on other
side
-VS-
-- electrical wave exactly replicating the waveform from those sound
sources - speaker cone - air in front of speaker.

First, what happens in the room:

Let's start out with an incredibly low frequency, loud source in the
room. We'll assume that this causes a waveform in the air with huge
pressure gradients that causes the diaphram to move in-out-in-out
relatively slowly with a very large amplitude.

While this is happening, we then start up a second source in the room,
which is high frequency, and lower amplitude. Assuming the air is 100%
linear, the two waveforms will add together perfectly.

However, when the higher frequency waveform (series of pressure
changes in the air) reaches the diaphragm, the diaphram is in *motion*
due to the low frequency source. This motion is relative to the high
frequency source, and therefore, instead of adding a perfect
representation of the high frequency waveform on top of the
diaphragm's movements, a *DOPPLER SHIFTED VERSION* of that high
frequency waveform appears on the diaphragm!

In other words, not only do speakers exhibit doppler distortion, but
microphone diaphragms would, as well! (if one does, then the other
should, too. This only makes sense). We generally don't care about it
with microphones, because the diaphragms move so slightly that it's
basically not there at all.

But in this thought experiment, it's there!

Now, on the other side of the wall, the diaphragm is vibrating a
doppler-distorted version of the original sounds. On this side, it
effectively acts like a speaker, and the waveform it's vibrating at
(the doppler distorted version of the original) is *again* doppler
distorted when going into the next room.

Now, I haven't done the math out on this, but I would suspect that any
doppler effects caused by the diaphragm "picking up" the waveform
would be *EXACTLY CANCELED OUT* by the doppler effects of the
diaphragm vibrating the air in the next room.

Net result: No doppler distortion through a diaphragm over a hole in
the wall!


Now, the speaker, on the other hand, exhibits the doppler distortion
going from speaker-air, with no "compensating" distortion on the
recording end, and therefore still exhibits doppler distortion. Well,
unless the microphone used the exact same transducer as the speaker to
record, and it had the same excursion -- then the doppler effect of
the microphone would cancel out the doppler effect of the speaker, and
the result would be an un-doppler-distorted recreation of the original
acoustic sound. HOWEVER, the resultant sound is *still* a doppler
distorted version of the *electrical* waveform, technically.

Unfortunately, your model is only true if you assume that everything
produces Doppler shift when at least two different frequencies are being
produced, a tuba and a flute, for example, and such a simply isn't true
because the fulte isn't inside the tuba moving with its vibrations, there is
NO Doppler distortion merely because there is a low frequency sound source
and a high frequency sound source in the same room (Doppler shift only
occurs when a high frequency sound source is riding on a separate low sound
source), and since our diaphragm is being driven by the complex acoustic
wave and producing an exact analog of the waveform in the listening room, no
Doppler shift is present there either. Since the speaker is being driven
with the exact electrical analog of the acoustic wave, it's cone movement is
exactly identical to the diaphragm over the hole, and therefore no Doppler
shift is produced in that case either.

"Bob Cain" wrote in message
...


The Ghost wrote:

"Porky" wrote in message
...

...And methinks The Ghost has protoplasmic porcine paskat for brains.
(I had to resort to Finnish to keep the alliteration going:-))
BTW, no point in replying to this because you've been *plonked*


Like I really give a rat's ass, you moron. Keep posting and join Bob
Cain in advertising your technical ignorance to the world.

You keep posting this kind of mindless, pathological drivel
when you offer absolutely nothing to indicate an iota of
technical acumen on your own part. Wow, you possibly set up
an experiment to show that somehow, somewhere in the process
a phase modulation occurs, but so what? That's not at all
in dispute.

How's about, just for kicks, giving us a derivation of the
theory you know and love with all axioms displayed for
critique, one that can predict what experiment will show?
You pretend to be the great theorist but have offered no
theory whatsoever.

As I've admitted I have no such detailed theory yet for the
principle I favor either, but then again I don't claim to be
a great theorist, just an independant thinker with a knack
for poking holes in shiboleths.


Actually, I think Bob and I have both demonstrated a certain acumen for
cutting through all the pseudo-academic bull**** and getting to the meat of
the matter. Of course, being a ghost and apparently being composed primarily
of ectoplasmic excrement, The Ghost would know little about the meat of
anything.
BTW, it being generally accepted that ghosts are non-corporeal, wouldn't
it follow that The Ghost's brain, and therefore his intellect, is also
non-corporeal?
(Gary may be of high intellect and a recognized expert in the field of
acoustics, but he has shown nothing in this thread but a foul temper and a
very immature attitude, he most certainly has posted nothing that might
indicate any expertise relevant to this discussion!)

This is a very interesting thought experiment! But I believe I have
the answer.

A diaphragm's movement caused by a sound wave on the other side of the
wall is *not* the same movement as a speaker's produced by the same
sound in electrical wave form.

Let's set up this situation:
-- Room with sound sources - Diaphragm over hole - air on other
side
-VS-
-- electrical wave exactly replicating the waveform from those sound
sources - speaker cone - air in front of speaker.

First, what happens in the room:

Let's start out with an incredibly low frequency, loud source in the
room. We'll assume that this causes a waveform in the air with huge
pressure gradients that causes the diaphram to move in-out-in-out
relatively slowly with a very large amplitude.

While this is happening, we then start up a second source in the room,
which is high frequency, and lower amplitude. Assuming the air is 100%
linear, the two waveforms will add together perfectly.

However, when the higher frequency waveform (series of pressure
changes in the air) reaches the diaphragm, the diaphram is in *motion*
due to the low frequency source. This motion is relative to the high
frequency source, and therefore, instead of adding a perfect
representation of the high frequency waveform on top of the
diaphragm's movements, a *DOPPLER SHIFTED VERSION* of that high
frequency waveform appears on the diaphragm!

In other words, not only do speakers exhibit doppler distortion, but
microphone diaphragms would, as well! (if one does, then the other
should, too. This only makes sense). We generally don't care about it
with microphones, because the diaphragms move so slightly that it's
basically not there at all.

But in this thought experiment, it's there!

Now, on the other side of the wall, the diaphragm is vibrating a
doppler-distorted version of the original sounds. On this side, it
effectively acts like a speaker, and the waveform it's vibrating at
(the doppler distorted version of the original) is *again* doppler
distorted when going into the next room.

Now, I haven't done the math out on this, but I would suspect that any
doppler effects caused by the diaphragm "picking up" the waveform
would be *EXACTLY CANCELED OUT* by the doppler effects of the
diaphragm vibrating the air in the next room.

Net result: No doppler distortion through a diaphragm over a hole in
the wall!


Now, the speaker, on the other hand, exhibits the doppler distortion
going from speaker-air, with no "compensating" distortion on the
recording end, and therefore still exhibits doppler distortion. Well,
unless the microphone used the exact same transducer as the speaker to
record, and it had the same excursion -- then the doppler effect of
the microphone would cancel out the doppler effect of the speaker, and
the result would be an un-doppler-distorted recreation of the original
acoustic sound. HOWEVER, the resultant sound is *still* a doppler
distorted version of the *electrical* waveform, technically.

Unfortunately, your model is only true if you assume that everything
produces Doppler shift when at least two different frequencies are being
produced, a tuba and a flute, for example, and such a simply isn't true
because the fulte isn't inside the tuba moving with its vibrations, there is
NO Doppler distortion merely because there is a low frequency sound source
and a high frequency sound source in the same room (Doppler shift only
occurs when a high frequency sound source is riding on a separate low sound
source), and since our diaphragm is being driven by the complex acoustic
wave and producing an exact analog of the waveform in the listening room, no
Doppler shift is present there either. Since the speaker is being driven
with the exact electrical analog of the acoustic wave, it's cone movement is
exactly identical to the diaphragm over the hole, and therefore no Doppler
shift is produced in that case either.

Yep I agree exactly. See my previous post in theis thread.

The membrane over the hole creates Doppler upon receiving the wave and
creates the opposite Doppler upon re-transmitting the wave.

It has nothing to do with coupling to the medium or the speed of the
Rx and Tx relative to the medium.

It's really very simple. Just look at the distance between the Rx and
Tx. If the distance between the Rx and Tx is changing, Doppler occurs
or should I say shift happens :-).


Mark

Ken Plotkin wrote:

On Mon, 23 Aug 2004 07:25:43 -0400, "Arny Krueger"
wrote:



Do you want to get the book for an affordable price, or do you want to make
a deal?

This book exudes a strong odor of "out of print".

That means that you look at $52.95, contemplate Amazon's ca. $200 asking
price, and do what you've got to do.


I already have a copy, which I bought new for $25.

As has been mentioned a couple of times, the book is available from
ASA for $30 (members) or $39 (non-members) and a link was provided
several posts back.

On order today from ASA with confimation that it is in
stock. Looking forward, thanks.


Bob
--

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

A. Einstein

Bob Cain wrote in message ...


You keep posting this kind of mindless, pathological drivel
when you offer absolutely nothing to indicate an iota of
technical acumen on your own part. Wow, you possibly set up
an experiment to show that somehow, somewhere in the process
a phase modulation occurs, but so what? That's not at all
in dispute.

How's about, just for kicks, giving us a derivation of the
theory you know and love with all axioms displayed for
critique, one that can predict what experiment will show?
You pretend to be the great theorist but have offered no
theory whatsoever.

I just thought I'd repost your sour-grapes temper tantrum in the event
that anyone may have missed it the first time around.

The Ghost wrote:

Bob Cain wrote in message ...



You keep posting this kind of mindless, pathological drivel
when you offer absolutely nothing to indicate an iota of
technical acumen on your own part. Wow, you possibly set up
an experiment to show that somehow, somewhere in the process
a phase modulation occurs, but so what? That's not at all
in dispute.

How's about, just for kicks, giving us a derivation of the
theory you know and love with all axioms displayed for
critique, one that can predict what experiment will show?
You pretend to be the great theorist but have offered no
theory whatsoever.


I just thought I'd repost your sour-grapes temper tantrum in the event
that anyone may have missed it the first time around.

I do note that you trimmed off your mindless, pathological
drivel, however. :-)

How about rising to the technical challenge instead of
tacking on more of it? I don't think you are capable.


Bob
--

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

A. Einstein

"Bob Cain" wrote in message
...


The Ghost wrote:

Bob Cain wrote in message
...



You keep posting this kind of mindless, pathological drivel
when you offer absolutely nothing to indicate an iota of
technical acumen on your own part. Wow, you possibly set up
an experiment to show that somehow, somewhere in the process
a phase modulation occurs, but so what? That's not at all
in dispute.

How's about, just for kicks, giving us a derivation of the
theory you know and love with all axioms displayed for
critique, one that can predict what experiment will show?
You pretend to be the great theorist but have offered no
theory whatsoever.


I just thought I'd repost your sour-grapes temper tantrum in the event
that anyone may have missed it the first time around.

I do note that you trimmed off your mindless, pathological
drivel, however. :-)

How about rising to the technical challenge instead of
tacking on more of it? I don't think you are capable.

Bob, you should know that ghosts aren't real, from his posts so far,
neither is his intellect!
Mr Ghost, I think Bob is trying to tell you to put up some evidence to
support your drivel... er, claims or quit wasting space in the newsgroups.

"Porky" wrote in message ...
capable.

Bob, you should know that ghosts aren't real, from his posts so far,
neither is his intellect!
Mr Ghost, I think Bob is trying to tell you to put up some evidence to
support your drivel... er, claims or quit wasting space in the newsgroups.

Grow a brain, you moron.

Bob Cain wrote in message ...

I do note that you trimmed off your mindless, pathological
drivel, however. :-)
How about rising to the technical challenge instead of
tacking on more of it? I don't think you are capable.
Bob

What you think is irrelevant. You have repeatedly demonstrated to the
world that you are nothing more than a technically inept scumbag who
is only capable of two things. One is irrational thought and the
other is making ad hominem attacks.

In my view, asking for evidence that support's one's view is NOT an
attack, As far as irrational thought, I've seen little to indicate any
particular rationality in your posts.

"The Ghost" wrote in message
om...
Bob Cain wrote in message
...

I do note that you trimmed off your mindless, pathological
drivel, however. :-)
How about rising to the technical challenge instead of
tacking on more of it? I don't think you are capable.
Bob

What you think is irrelevant. You have repeatedly demonstrated to the
world that you are nothing more than a technically inept scumbag who
is only capable of two things. One is irrational thought and the
other is making ad hominem attacks.

"Porky" wrote in message ...
In my view, asking for evidence that support's one's view is NOT an
attack, As far as irrational thought, I've seen little to indicate any
particular rationality in your posts.


The evidence is there, just refuse to accept it. Additionally, there
is nothing in any of your your posts to indicate that you even know
what rational thought is. No surprise that you aren't able to
recognize it.

"Porky" wrote in message ...
In my view, asking for evidence that support's one's view is NOT an
attack, As far as irrational thought, I've seen little to indicate any
particular rationality in your posts.


The evidence is there, just refuse to accept it. Additionally, there
is nothing in any of your your posts to indicate that you even know
what rational thought is. No surprise that you aren't able to
recognize it.

Bob Cain wrote in message ...
The Ghost wrote:

Art Ludwig DOES NOT agree with your position on this issue, and you
need to post the retraction/correction as he has requested.

Not sure where you got that. The last email I have from him
(yesterday) tells me we are in substantial agreement. Yes,
there were still some disagreements but the essentials of
what I've posted here were corroborated.

If that has changed, he has not told me about it (or if it
is posted here I haven't seen it yet) and if he does, I will
most certainly report that here.
Bob

For those who are interested in knowing what Art Ludwig really believes, see:
http://www.silcom.com/~aludwig/Physi...on/dopdist.htm

Bob Cain has known this all along, but he is ego wouldn't let him admit it.

Bob Cain wrote in message ...
I do note that you trimmed off your mindless, pathological
drivel, however. :-)

How about rising to the technical challenge instead of
tacking on more of it? I don't think you are capable.

You are technically inept and completely incapable of rational
thought. As is evidenced by your past 3-4 year record, all you are
capable of doing is making ad hominem attacks. Accordingly, what YOU
think is irrelevant.

"The Ghost" wrote in message
om...
Bob Cain wrote in message
...
I do note that you trimmed off your mindless, pathological
drivel, however. :-)

How about rising to the technical challenge instead of
tacking on more of it? I don't think you are capable.

You are technically inept and completely incapable of rational
thought. As is evidenced by your past 3-4 year record, all you are
capable of doing is making ad hominem attacks. Accordingly, what YOU
think is irrelevant.

There once was a movie with the title, "The Ghost and Mister Chicken",
however, in this case it would seem that The Ghost is Mister Chicken. He
keeps throwing out insults and when challenged to present facts, he evades
with more insults. He might be one of the most brilliant minds of our time,
but if so, he hides it very well indeed! :-)

"Porky" wrote in message ...

There once was a movie with the title, "The Ghost and Mister Chicken",
however, in this case it would seem that The Ghost is Mister Chicken. He
keeps throwing out insults and when challenged to present facts, he evades
with more insults. He might be one of the most brilliant minds of our time,
but if so, he hides it very well indeed! :-)

Perhaps you should take some lessons from The Ghost, because you are
doing a ****-poor job of hiding your ignorance. Clearly, when the
Allmighty was handing out brains, you were standing in the wrong line.

"The Ghost" wrote in message
om...
"Porky" wrote in message
...

There once was a movie with the title, "The Ghost and Mister Chicken",
however, in this case it would seem that The Ghost is Mister Chicken. He
keeps throwing out insults and when challenged to present facts, he
evades
with more insults. He might be one of the most brilliant minds of our
time,
but if so, he hides it very well indeed! :-)

Perhaps you should take some lessons from The Ghost, because you are
doing a ****-poor job of hiding your ignorance. Clearly, when the
Allmighty was handing out brains, you were standing in the wrong line.

You know, I'm going to be a man here and apologize to you for the personal
insults I've posted here. I don't know you and you don't know me. The tone
of your posts to Bob and to me have been belittling and insulting and I just
replied in kind, which really makes me no better (but no worse) than you. If
you have specific objections to things I've posted, refute them in a logical
manner. For a start do you deny that the train/whistle model is different
from the hole in the wall model as far as Doppler shift is concerned, and if
so, why? Complex math isn't necessary, if there's a mistake in my logic,
point it out in logical terms. If I see that you're right, I'll admit it and
the discussion can turn to other things. If I see a flaw in your logic, I'll
try to clarify and point it out.
However, don't make the mistake of thinking I'm beneath you, I'll
guarantee you I can out insult you any time (I have a post-doctorate degree
in Applied Insults from the University of Hard Knocks:-)), and on
visualizing the mechanics of how things work, I might be your equal, or even
a bit ahead of you, even if I don't have the math and physics education to
formulate the equations.

Ben Bradley wrote:

fd = f*c/(c + v),

Randy, that equation is only defined for a static v.


So if you start changing v, the doppler effect stops until you
leave v alone for a while? How does the doppler effect know to stop
and start up again?

C'mon, Ben. Where did I imply that it stops and starts?
That equation just can't tell the whole story. Consider
that for v constant none of its motion is being imparted to
the wave that reaches the Rx but if it is oscilating, some
of it is. That has to make some difference in the net
effect beyond the predicted warble. That difference is
missing from the equation because it is a term which drops
out for dv/dt=0. Can I derive that yet, no. Am I sure
there are additional terms dependant on rate of change, or
multiplied by w if two tones, yes.


Seriously (or you can answer the above question seriously if you
like), do you have any reference for the equation being defined only
for v being static?

I'm still awiating Pierce's book wherin it is claimed that
it is derived for the fully dynamic case giving the same
result. All the derivations I somewhat remember from long
ago university freshman physics definitely assumed constant
v as a premise.

The main reason I'm working out the proof of why Doppler
mixing doesn't happen with a piston in a tube is that the
equation above will thus be violated. After it has ramped
up from a stationary position to where it is oscilationg
with a constant motion superimposed on it, and after that
ramping up has passed an observer at some distance from the
piston, he will see no change in frequency but instead the
same oscilation superimposed on a constant air velocity
(until the piston smacks him up 'long side the head if the
constant motion is toward him.)

I'm pretty sure I now have that proof but am sitting with it
a while instead of possibly jumping the gun again and I've
asked a few folks to sanity check it. Would you care to?


Bob
--

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

A. Einstein

Bob Cain wrote:

After it has ramped up from a stationary position to where it
is oscilationg with a constant motion superimposed on it, and after that
ramping up has passed an observer at some distance from the piston, he
will see no change in frequency but instead the same oscilation
superimposed on a constant air velocity (until the piston smacks him up
'long side the head if the constant motion is toward him.)

Ouch! That's dead wrong. Compass drift. With this problem
it is really difficult staying in the correct frame of
reference and when I wrote that I'd partially stepped off a
stationary one onto one that was moving, one foot still
firmly in each. :-)


Bob
--

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

A. Einstein

Bob Cain writes:

Ben Bradley wrote:

fd = f*c/(c + v),

Randy, that equation is only defined for a static v.
So if you start changing v, the doppler effect stops until you
leave v alone for a while? How does the doppler effect know to stop
and start up again?

C'mon, Ben. Where did I imply that it stops and starts?

When you stated

Randy, that equation is only defined for a static v.

I had the same impression as Ben.
--
% Randy Yates % "...the answer lies within your soul
%% Fuquay-Varina, NC % 'cause no one knows which side
%%% 919-577-9882 % the coin will fall."
%%%% % 'Big Wheels', *Out of the Blue*, ELO
http://home.earthlink.net/~yatescr

Randy Yates wrote:

Bob Cain writes:


Ben Bradley wrote:


fd = f*c/(c + v),

Randy, that equation is only defined for a static v.

So if you start changing v, the doppler effect stops until you
leave v alone for a while? How does the doppler effect know to stop
and start up again?

C'mon, Ben. Where did I imply that it stops and starts?


When you stated

Randy, that equation is only defined for a static v.

I had the same impression as Ben.

Ah, I see. The word "valid" would have been much clearer
than "defined" then. A point to remember, thanks.

I hope it's clear now that I don't mean that the effect
stops, but rather that the common equation describing it
stops being the correct one.


Bob
--

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

A. Einstein

The Ghost wrote:

Bob Cain wrote in message ...

fd = f*c/(c + v),

Randy, that equation is only defined for a static v.


You say that with such authority, but you most certainly don't have
the authority required to make such a bold assertion. Can you
provide a reference to the technical literature to support such a
claim? The answer is no, because no such reference exists. The fact
of the matter is that your assertion is nothing more than a personal
belief, which you have accepted without questioning its validity.
Had you looked into it, as I have, you would have discovered that the
equation applies under both constant velocity and dynamic velocity
conditions. You will find the derivation in Allan Pierce's book
entitled "Acoustics: An Introduction to Its Physical Principles and
Applications."

To be more precise it says on page 453, "The source does not
have to be traveling with constant velocity or in a straight
line for Eq. (5) to apply; however, determination of the
point on trajectory from which the wavelet originates
requires additional labor to match the kinematics, possibly
a graphical solution if the motion is not rectilinear."

I would add "and not constant."

He disqualifies the whole section for direct application to
a local analysis of a superimposed HF and LF signal in the
third sentence of the section. I'll leave it as an exercise
for the student to figure out what is wrong with the way fd
= f*c/(c + v) has been applied to that analysis. For now
that is. :-)


Bob
--

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

A. Einstein