The Ghost wrote:

If I were you, I wouldn't expect any help on other problems
from Art anytime soon.

Do you speak for Art Ludwig now? Have you, at any point,
spoken _as_ Art Ludwig?


Bob
--

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

A. Einstein

"The Ghost" wrote in message
. 29...
"Jim Carr" wrote in
newson8d.12144$mS1.11114@fed1read05:

"The Ghost" wrote in message
. 29...

You have recently called me a fraud. Perhaps it is you who is the real
fraud? If not, prove it.

Hmmm...Celebrating in Art's shadow and insulting people does not help
you
shed the overcoat of fraud. Y

Screw you, asswipe. All you've ever offered is mindless, ignorant arm-
chair criticism. So, you don't even qualify for the fraud test.


You've still offered nothing beyond putting
together an experiment that demonstrated what everyone in the discussion
agreed upon already.

Quite the contrary, At the time everyone in your mindless camp was
denying
the mere existence of dynamic Doppler shift. Shortly after I presented my
measurement results, the tune immediately changed. The new tune became
that Doppler distortion did exist, but not in a tube. Now that two people
have independently presented theoretical predicitions of the levels of
Doppler distiortion in a tube, the tune has once again changed.

Kiss my ass you technically-inept piece of ****. You are so full of it
that it is flowing out your ears.

I would suggest that you take a bottle or two of Immodium AD, your oral
diarrhea is really getting out of control again. You're losing the race, the
human race, that is...

"Vladan" wrote in message
...
After so many words spent on the effect in regard to speaker, when are
you to start examining it in regard to (dynamic) microphone.

And don't forget the air. Molecules are moving. There must be some
dopler there, too.
In a microphone, the diaphragm excursion is so small that any possible
Doppler shift would be negligable, even assuming that there is Doppler shift
in a mic. BTW, if there is Doppler shift in a microphone because of
diaphragm excursion, then there must also be Doppler shift in the human ear
because of the excursion of the eardrum, and if that is true, our hearing
mechanism must have compensation built in, so, since the amount of excursion
in the mic and the eardrum are similar, if there is any Doppler shift in a
mic, it can be disregarded.

"The Ghost" wrote in message
. 29...

Screw you, asswipe. All you've ever offered is mindless, ignorant arm-
chair criticism. So, you don't even qualify for the fraud test.

I have stated from day one that I understand the concept of Doppler
distortion in a speaker as repeatedly described. I also commented that if it
happens as described, then microphones suffer from it. Instruments like
guitars and pianos must also suffer from it as well. However, because of the
short distances in the vibrations, it must not be much.

What bothered me was that I could not (and still cannot) see how a speaker
really works. Yeh, I can describe the mechanics involved, but I still don't
fully understand the exact physics where the diaphragm creates the sound
wave. Is it at the start of the throw? The end? The middle? If it's in the
middle of a long throw for a loud low frequency, how does it make the higher
frequencies at the same time?

The speaker pushes air and makes a breeze, but it also transfers energy to
individual molecules which start bouncing into each other in a wave, which
is what we ultimately perceive as sound. I accept that it works, but the
physics escape me. I can live with that.

So, when Bob suggested that there might be something more involved with
Doppler distortion due the physics described above, I thought that was a
fair question to ask. He conducted himself quite well and took the humble
step of expanding the discussion out of a.m.h-s and into groups where people
with expertise greater than his might answer the question.

It was going quite well until some home-schooled, insecure mamma's boy (that
would be you) started venting his years of frustration and feelings of
inadequacy. It's been a fun little game watching you yap like a poodle while
several of us kicked the fence. FYI, Porky and I are far from being pals.
Check the Google archives if you don't believe me.

I have stated repeatedly that I have neither the training nor the experience
to even begin to answer the questions myself. Quite frankly I couldn't care
less if it's there or not. First, I cannot hear it. Second, even if I could,
there's nothing I could do about it anyway. Of the issues in the processes
required for me to produce good music on my home computer, Doppler
distortion is at the bottom of the list.

So, there is no fraud test for me to pass or fail. Well, maybe there is.
Maybe I am lying and really do have a degree in physics, and I'm just
playing dumb. Sorta like you, I guess.

As for your blustering about threats, give it a rest. There's no way you
have the balls to say in person any of the things you've written. You might
have when you were younger, but now you're too big to hide in your mother's
apron when things get tough. You know deep down I'm right, so don't even
bother playing the "if we met in person" game. Chances are it would never
happen. If it did, we all know how you'd behave.

Kiss my ass you technically-inept piece of ****. You are so full of it
that it is flowing out your ears.

Try something new, will ya? That one is getting old.

Porky wrote:

"Vladan" wrote in message
...

After so many words spent on the effect in regard to speaker, when are
you to start examining it in regard to (dynamic) microphone.

And don't forget the air. Molecules are moving. There must be some
dopler there, too.

In a microphone, the diaphragm excursion is so small that any possible
Doppler shift would be negligable, even assuming that there is Doppler shift
in a mic.

Nonetheless, even if the mic can measure pressure or
velocity at a point with zero excursion there is still a
non-linear relationship between the motion of a tiny
zero-mass test particle normally at rest at that point and
the pressure/velocity measured there. Remaining tubular for
the nonce, if we had a mixture of a 40 Hz and a 2 kHz wave
each at 94 dB SPL and if the motion of the test particle is
that of the signal then the pressure at its rest position
will show about 0.024% IM distortion relative to the HF
fundamental and sidebands about -75 dB down from it.

The thing that concerns me, now that I can put numbers to at
least the tube conditions and see that they can get big, is
that if conditions are such that in the very near field of a
speaker a signifigant percentage of its LF velocity is
coupled to the air then the Doppler effect can get _very_
signifigant because of the large excursions needed to offset
the poor far field coupling. My hope is that a retarded
wave cancels most of that up close so that it won't grow to
too great a signifigance.

The degree of near field LF coupling for a given far field
measure from a speaker in an enclosure is the next thing I
want to know.


Bob
--

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

A. Einstein

"Porky" wrote in message
...
In a microphone, the diaphragm excursion is so small that any possible
Doppler shift would be negligable, even assuming that there is Doppler
shift
in a mic. BTW, if there is Doppler shift in a microphone because of
diaphragm excursion, then there must also be Doppler shift in the human
ear
because of the excursion of the eardrum, and if that is true, our hearing
mechanism must have compensation built in, so, since the amount of
excursion
in the mic and the eardrum are similar, if there is any Doppler shift in a
mic, it can be disregarded.

What a load of crap. Whilst I agree that any doppler in a microphone would
be minute, it would not be compensated for by the ear/brain just because it
may be similar magnitude to the eardrum.

TonyP.

"Bob Cain" wrote in message
...


Porky wrote:

"Vladan" wrote in message
...

After so many words spent on the effect in regard to speaker, when are
you to start examining it in regard to (dynamic) microphone.

And don't forget the air. Molecules are moving. There must be some
dopler there, too.

In a microphone, the diaphragm excursion is so small that any possible
Doppler shift would be negligable, even assuming that there is Doppler
shift
in a mic.

Nonetheless, even if the mic can measure pressure or
velocity at a point with zero excursion there is still a
non-linear relationship between the motion of a tiny
zero-mass test particle normally at rest at that point and
the pressure/velocity measured there. Remaining tubular for
the nonce, if we had a mixture of a 40 Hz and a 2 kHz wave
each at 94 dB SPL and if the motion of the test particle is
that of the signal then the pressure at its rest position
will show about 0.024% IM distortion relative to the HF
fundamental and sidebands about -75 dB down from it.

If we get into Doppler shift due to motion in air molecules, I suspect
we're getting down to "the bumble bee doesn't really fly because the math
says it can't" point.

The thing that concerns me, now that I can put numbers to at
least the tube conditions and see that they can get big, is
that if conditions are such that in the very near field of a
speaker a signifigant percentage of its LF velocity is
coupled to the air then the Doppler effect can get _very_
signifigant because of the large excursions needed to offset
the poor far field coupling. My hope is that a retarded
wave cancels most of that up close so that it won't grow to
too great a signifigance.

The degree of near field LF coupling for a given far field
measure from a speaker in an enclosure is the next thing I
want to know.

If the equations show that all that much Doppler distortion in a speaker,
why can't we hear it?
By Occam's Rasor, either our hearing mechanism has built in compensation,
so Doppler distortion doesn't matter, or the math is wrong and it needs to
be revised. That isn't to say that it doesn't happen in the
piston-in-an-infinite-tube model, it just means that the speaker/room model
is a totally different animal.

"TonyP" wrote in message
u...

"Porky" wrote in message
...
In a microphone, the diaphragm excursion is so small that any possible
Doppler shift would be negligable, even assuming that there is Doppler
shift
in a mic. BTW, if there is Doppler shift in a microphone because of
diaphragm excursion, then there must also be Doppler shift in the human
ear
because of the excursion of the eardrum, and if that is true, our
hearing
mechanism must have compensation built in, so, since the amount of
excursion
in the mic and the eardrum are similar, if there is any Doppler shift in
a
mic, it can be disregarded.

What a load of crap. Whilst I agree that any doppler in a microphone would
be minute, it would not be compensated for by the ear/brain just because
it
may be similar magnitude to the eardrum.

It seems that you missed the point, which was that if there is Doppler
shift in a mic because of diaphragm motion, then there must also be Doppler
shift in the human ear
because of eardrum motion. If that is true then the hearing mechanism must
have a method of compensation for it.

Bob Cain wrote in message ...

Hi, Bob,

Just a minor correction.

Please notice the difference between what I wrote and what
Zigoteau wrote. His approach, a first order approximation
using a M-T power series, yields (using common symbols and
frames of reference):

Vp(d,t) = Vd(t - (d - Sd(t-d/c))/(c - Vd(t-d/c)))

Mine, which involves no approximation, yields:

Vp(d,t) = Vd(t - (d - Sd(t-d/c))/c)

I am sorry, Bob, but the second equation does involve an approximation.

Cheers,

Zigoteau.

"Porky" wrote in message
...
It seems that you missed the point, which was that if there is Doppler
shift in a mic because of diaphragm motion, then there must also be
Doppler
shift in the human ear
because of eardrum motion. If that is true then the hearing mechanism must
have a method of compensation for it.

It seems you've missed my point. The brain "compensates" for the auditory
system itself, because you have NO other point of reference.

TonyP.