Experimental Evidence for Dynamic Doppler Shift
The Ghost
Assuming that the equation for the Doppler frequency shift of a source
moving at constant velocity also applies under dynamically changing
velocity conditions, one would expect the propagating sound, that is
produced by a high-frequency source moving dynamically at a low
frequency around a fixed position, to be frequency modulated. One
would further expect that the instantaneous frequency of the
propagating sound would reflect the dynamic low-frequency velocity the
source. If so, the waveform of the fm-demodulated high-frequency
propagating sound, should follow on an instantaneous basis, the
dynamic velocity of the low-frequency velocity of the source.
THE SETUP:
A small circular piezoelectric bimorph, having a resonant frequency of
approximately 10KHz was attached to the 10-lb armature/shaft of a
linear motor. The displacement of the armature/shaft was monitored
by a linear displacement transducer attached to the opposite end of
the armature/shaft. The linear displacement transducer also provided
feedback for the servo amplifier which was driving the linear motor.
Because the linear motor was in a servo loop, the displacement of the
motor followed with reasonable accuracy both sinusoidal and
non-sinusoidal command signals that were applied to the amplifier.
The piezoelectric sound source was driven by a low-distortion
oscillator at 10KHz. The sound emitted by the source was measured by a
microphone at a distance of approximately one foot. The output of the
microphone was amplified, high-pass filtered and applied to a
frequency-to-voltage converter. The output of the
frequency-to-voltage converter was low-pass filtered to reduce the
level of the residual 10KHz carrier, amplified and applied to a signal
averager. The signal averager was triggered by the command signal
that was applied to the linear motor. Averaging was used in order to
remove non-coherent 60Hz that was present in the output of the
demodulator.
THE MOTION OF THE SOUND SOURCE
A triangular command signal having a 50-msec period was applied to the
servo amplifier. A triangular command signal was used in order to
simplify interpretation of the measurement result and to avoid the
phase shift vs time delay ambiguity that would otherwise exist with
fixed frequency sinusoidal excitation. The output of the displacement
transducer was monitored on an oscilloscope and found to be triangular
with rounded corners. The rounding of the corners is due to the
limited closed-bandwidth of the servo. The velocity of the linear
motor was therefore trapezoidal with relatively flat and relatively
long plateaus and relatively short transitions.
THE MEASUREMENT RESULT
The propagating 10KHz signal emitted by the piezo bimorph was applied
to an FFT analyzer in zoom-analysis mode with a resolution bandwidth
of 0.1Hz. When the piezo bimorph was stationary, the propagating
signal picked up by the microphone showed only a single spectral peak
at 10KHz. When the piezo transducer was moving back and forth with a
triangular displacement provided by the linear motor, the propagating
signal received by the microphone contained numerous sidebands which
were indicative of FM modulation. Additionally, the output of the FM
demodulator was observed to be trapezoidal and followed on an
instantaneous basis the velocity of the linear motor and the attached
piezo transducer.
THE CHALLENGE
In science, theory usually follows experimental results. In this case
the experimental result shows that a 10KHz signal applied to a small
piezoelectric source moving back and forth around a fixed position
becomes frequency modulated by the back and forth motion of the
source. The measurement further shows that the received,
FM-demodulated signal follows the instantaneous velocity of the
source. This result is exactly what is expected on the basis of
Doppler frequency shift extrapolated from constant velocity to dynamic
velocity conditions. While some might argue that the observed
FM-like sidebands and the trapezoidal demodulated waveform are the
result of IM distortion, and not Doppler FM, the ball is in their
court. It is now up to them to provide an explanation/analysis
involving an IM producing mechanism in the present experimental setup
that accounts for the present experimental result. Finally, it must
be noted that the purpose of the present measurement was to
demonstrate fundamental phenomenological behavior. The 10KHz carrier
and the 50-msec peridiocity for the displacement of the linear motor
were chosen solely to accommodate the hardware on hand. There is
presently no reason to believe that the outcome of the present
measurement would be different if other carrier frequencies or other
source displacement periodicities or waveshapes were used.
Karl Uppiano
"The Ghost" <the_gho...@netzero.com> wrote in message
news:b5fb78ba.04081...@posting.google.com...
This experiment is very "pure", and in fact, pretty much *defines* the
Doppler effect and frequency modulation. To determine its relevance to audio
applications, someone now needs to add additional parameters. For example:
o It would be interesting to observe the results when the modulating
frequency and the carrier are close together in frequency, and the sidebands
significantly overlap the modulating frequency, as they would in a typical
loudspeaker.
o Is the Doppler effect of the same order of magnitude of other loudspeaker
nonlinearities, such as harmonic and intermodulation distortion? How
difficult is it to resolve these effects separately when occurring
simultaneously in the same loudspeaker?
o How much do multi-way speakers mitigate these effects? Are wide-range
drivers measurably worse in these effects? (My intuition predicts that they
will be, but some full range speakers manage to employ mechanical
crossovers -- but I would expect them to be ineffective in reducing Doppler
intermodulation distortion). For what it's worth, what we commonly refer to
as "intermodulation distortion" is "amplitude intermodulation distortion"
(AIM). Speakers are the only device that I'm aware of that would exhibit
measurable Doppler intermodulation distortion, or DIM.
o Are horn speakers (including low frequency horns, like Klipschorns) less
susceptible to DIM due to the fact that they're more efficient, and require
less diaphragm motion for a given SPL?
ruffrecords
> THE HYPOTHESIS:
> Assuming that the equation for the Doppler frequency shift of a source
> moving at constant velocity also applies under dynamically changing
> velocity conditions, one would expect the propagating sound, that is
> produced by a high-frequency source moving dynamically at a low
> frequency around a fixed position, to be frequency modulated. One
> would further expect that the instantaneous frequency of the
> propagating sound would reflect the dynamic low-frequency velocity the
> source. If so, the waveform of the fm-demodulated high-frequency
> propagating sound, should follow on an instantaneous basis, the
> dynamic velocity of the low-frequency velocity of the source.
>
>
major snippage.
here we go again.
The flaw in this argument is that this set up assumes it is the same as
the linear superposition of the of the two signals in a single
transducer. it is not.
Ian
Karl Uppiano
> the linear superposition of the of the two signals in a single transducer.
> it is not.
A single loudspeaker reproducing the linear sum of two different
frequencies. The higher frequency "riding" back and forth on the lower
frequency. Will that not affect the wavelength of the higher frequency as a
function motion of the diaphragm due to the lower frequency, assuming the
speed of sound in air remains constant under these conditions?
ruffrecords
Go look in a good text book for the words 'linear' and 'sum'
Ian
Karl Uppiano
"ruffrecords" <ruffr...@yahoo.com> wrote in message
news:cfpinp$vrf$1...@slavica.ukpost.com...
Why don't you just answer my question, and forego the superior attitude? I'm
sure you can figure out what I meant.
ruffrecords
OK. No, otherwise it would not be a linear sum. Hence my reading
suggestion.
Ian
Karl Uppiano
I understand what "linear" and "sum" mean. When modulated by two sinusoids,
the x position of the diaphragm as a function of time is defined by
x( t ) = A sin( w1 t ) + B sin( w2 t )
Where A and B are the amplitudes of the two frequencies, and w2 and w2 are
the frequencies in radians per second of the two frequencies. Let's call w1
the low frequency and w2 the high frequency. There are no non-linear terms
in this equation, so we won't get harmonic or IM distortion. I understand
that.
Since Doppler shift is based on the velocity, not the position of the
diaphragm, we must differentiate this equation. The velocity of the
diaphragm as a function of time is then
v( t ) = w1 A cos( w1 t ) + w2 B cos( w2 t )
The formula for Doppler shift is
ls = lo ( 1 - ( vs / c ) )
where
ls = the resulting wavelength (lambda shifted)
lo = the original wavelength of the higher frequency (lambda original)
vs = the velocity of the source (diaphragm velocity)
c = is the speed of sound in air
therefore, substituting v(t) for vs,
ls( t ) = lo ( 1 - ( ( w1 A cos( w1 t ) + w2 B cos( w2 t ) ) / c ) )
which appears to my eye as a time-varying wavelength based on the diaphragm
velocity. What am I doing wrong?
Karl Uppiano
Reposting this, since it didn't appear to "take" last time:
Bob Cain
Karl Uppiano wrote:
> I understand what "linear" and "sum" mean. When modulated by two sinusoids,
> the x position of the diaphragm as a function of time is defined by
>
> x( t ) = A sin( w1 t ) + B sin( w2 t )
It is the piston velocity v(t) that follows this for equal
sound pressure at all frequencies.
>
> Where A and B are the amplitudes of the two frequencies, and w2 and w2 are
> the frequencies in radians per second of the two frequencies. Let's call w1
> the low frequency and w2 the high frequency. There are no non-linear terms
> in this equation, so we won't get harmonic or IM distortion. I understand
> that.
>
> Since Doppler shift is based on the velocity, not the position of the
> diaphragm, we must differentiate this equation. The velocity of the
> diaphragm as a function of time is then
>
> v( t ) = w1 A cos( w1 t ) + w2 B cos( w2 t )
That would be the acceleration a(t) which has no acoustic
consequences.
I'm too tired right now to follow those corrections all the
way through the rest of your welcome attempt to quantify
this but would you consider working them through to the
conclusion you can reach?
Thanks,
Bob
--
"Things should be described as simply as possible, but no
simpler."
A. Einstein
Karl Uppiano
"Bob Cain" <arc...@arcanemethods.com> wrote in message
news:cfsb5...@enews3.newsguy.com...
>
>
> Karl Uppiano wrote:
>
>
>> I understand what "linear" and "sum" mean. When modulated by two
>> sinusoids, the x position of the diaphragm as a function of time is
>> defined by
>>
>> x( t ) = A sin( w1 t ) + B sin( w2 t )
>
> It is the piston velocity v(t) that follows this for equal sound pressure
> at all frequencies.
Hmmm... what is the equation for x( t ) then?
>>
>> Where A and B are the amplitudes of the two frequencies, and w2 and w2
>> are the frequencies in radians per second of the two frequencies. Let's
>> call w1 the low frequency and w2 the high frequency. There are no
>> non-linear terms in this equation, so we won't get harmonic or IM
>> distortion. I understand that.
>>
>> Since Doppler shift is based on the velocity, not the position of the
>> diaphragm, we must differentiate this equation. The velocity of the
>> diaphragm as a function of time is then
>>
>> v( t ) = w1 A cos( w1 t ) + w2 B cos( w2 t )
>
> That would be the acceleration a(t) which has no acoustic consequences.
Isn't velocity the first derivative of position? Isn't acceleration the
first derivative of velocity? It seems that acceleration (if we cared about
it) would be
a( t ) = - ( w1^2 A sin( w1 t ) + w2^2 B sin( w2 t ) )
However, all three equations only differ by a constant. So I believe you
could get the same physical consequences by simply adjusting A and B
accordingly.
> I'm too tired right now to follow those corrections all the way through
> the rest of your welcome attempt to quantify this but would you consider
> working them through to the conclusion you can reach?
My end result would differ by a constant (i.e., it would have a different
magnitude), as I mentioned above, but I believe the phenomenon would be the
same.
Bob Cain
Karl Uppiano wrote:
> "Bob Cain" <arc...@arcanemethods.com> wrote in message
> news:cfsb5...@enews3.newsguy.com...
>
>>
>>Karl Uppiano wrote:
>>
>>
>>
>>>I understand what "linear" and "sum" mean. When modulated by two
>>>sinusoids, the x position of the diaphragm as a function of time is
>>>defined by
>>>
>>> x( t ) = A sin( w1 t ) + B sin( w2 t )
>>
>>It is the piston velocity v(t) that follows this for equal sound pressure
>>at all frequencies.
>
>
> Hmmm... what is the equation for x( t ) then?
x( t ) = -(A/w1) cos( w1 t ) - (B/w2) cos( w2 t )
> Isn't velocity the first derivative of position? Isn't acceleration the
> first derivative of velocity? It seems that acceleration (if we cared about
> it) would be
>
> a( t ) = - ( w1^2 A sin( w1 t ) + w2^2 B sin( w2 t ) )
Try
a( t ) = w1 A cos( w1 t ) + w2 B cos( w2 t )
>
> However, all three equations only differ by a constant. So I believe you
> could get the same physical consequences by simply adjusting A and B
> accordingly.
And phase. The adjustment to A and B is a constant if W is.
Karl Uppiano
>
>
> Karl Uppiano wrote:
>
>> "Bob Cain" <arc...@arcanemethods.com> wrote in message
>> news:cfsb5...@enews3.newsguy.com...
>>
>>>
>>>Karl Uppiano wrote:
>>>
>>>
>>>
>>>>I understand what "linear" and "sum" mean. When modulated by two
>>>>sinusoids, the x position of the diaphragm as a function of time is
>>>>defined by
>>>>
>>>> x( t ) = A sin( w1 t ) + B sin( w2 t )
>>>
>>>It is the piston velocity v(t) that follows this for equal sound pressure
>>>at all frequencies.
>>
>>
>> Hmmm... what is the equation for x( t ) then?
>
> x( t ) = -(A/w1) cos( w1 t ) - (B/w2) cos( w2 t )
...which I assume you arrived at by integrating my original equation. Is
there a derivation of this somewhere that I can look up?
>> Isn't velocity the first derivative of position? Isn't acceleration the
>> first derivative of velocity? It seems that acceleration (if we cared
>> about it) would be
>>
>> a( t ) = - ( w1^2 A sin( w1 t ) + w2^2 B sin( w2 t ) )
>
> Try
>
> a( t ) = w1 A cos( w1 t ) + w2 B cos( w2 t )
>
>>
>> However, all three equations only differ by a constant. So I believe you
>> could get the same physical consequences by simply adjusting A and B
>> accordingly.
>
> And phase. The adjustment to A and B is a constant if W is.
Right. Bottom line, though, it seems that the wavelength is still a
time-varying function of the diaphragm velocity. Now, I need to understand
how the diaphragm motion is converted into sound. I will accept the
possibility that somehow the motion is irrelevant to the wavelength, but I
need to see the physics.
Bob Cain
Karl Uppiano wrote:
> "Bob Cain" <arc...@arcanemethods.com> wrote in message
> news:cfthq...@enews3.newsguy.com...
>
>>
>>Karl Uppiano wrote:
>>
>>
>>>"Bob Cain" <arc...@arcanemethods.com> wrote in message
>>>news:cfsb5...@enews3.newsguy.com...
>>>
>>>
>>>>Karl Uppiano wrote:
>>>>
>>>>
>>>>
>>>>
>>>>>I understand what "linear" and "sum" mean. When modulated by two
>>>>>sinusoids, the x position of the diaphragm as a function of time is
>>>>>defined by
>>>>>
>>>>> x( t ) = A sin( w1 t ) + B sin( w2 t )
>>>>
>>>>It is the piston velocity v(t) that follows this for equal sound pressure
>>>>at all frequencies.
>>>
>>>
>>>Hmmm... what is the equation for x( t ) then?
>>
>> x( t ) = -(A/w1) cos( w1 t ) - (B/w2) cos( w2 t )
>
>
> ...which I assume you arrived at by integrating my original equation. Is
> there a derivation of this somewhere that I can look up?
Yes. I just noted that for frequency independant operation
it is the velocity that should have been modeled with your
equation, not the position. x( t ) and a( t ) follow by
differentiation and integration respectively.
>>
>>And phase. The adjustment to A and B is a constant if W is.
>
>
> Right. Bottom line, though, it seems that the wavelength is still a
> time-varying function of the diaphragm velocity.
Why would the wavelength vary over time? If you drive the
piston with a fixed magnitude sinusoid, its wavelength is
fixed and so is that of the acoustic wave it puts out unless
it moves with constant velocity relative to the air. If
driven with any periodic function, the period is determined
by the lowest Fourier component.
The velocity of that piston is converted into an acoustic
wave with the same shape as that of the piston's velocity
function.
If it is in constant linear translation, the wave function
will be an expanded or contracted version of the piston's
velocity function. That's Doppler shift.
Karl Uppiano
Is there a web site that would describe the physics, mathematically, of how
diaphragm motion is converted to sound? And more specifically, with two
frequencies, how the time-varying velocity of the lower frequency would not
Doppler-shift the higher one? I just want to understand the physics of this,
and get at the truth of the matter.
Bob Cain
Karl Uppiano wrote:
> Is there a web site that would describe the physics, mathematically, of how
> diaphragm motion is converted to sound?
If you are up to it:
http://www.silcom.com/~aludwig/Physics/Main/Physics_of_sound.html
I haven't printed it off and holed up with it yet and I've
got to do that.
> And more specifically, with two
> frequencies, how the time-varying velocity of the lower frequency would not
> Doppler-shift the higher one? I just want to understand the physics of this,
> and get at the truth of the matter.
The piston doesn't know from two frequencies. It knows and
transfers its instantaneous velocity to the correct position
of the outward propegating wave. It doesn't care what was
mixed to get that velocity and it doesn't care what came
before or after that instant.
If you can make the piston move the way you want you can get
it to produce the acoustic wave you want.
Karl Uppiano
Since this thread was started, it has meandered here and there, and I just
realized that we may have jumped to some invalid conclusions. Here are some
important points to consider:
1. I believe this experiment is relevant in that we should be able to
mathematically predict and experimentally measure frequency modulation due
to Doppler shifts with a good degree of agreement within the constraints
this setup (i.e., a linear motor pushing a peizo radiator back and forth).
It is not clear whether the OP was able to correlate the experimental
results with the mathematical predictions, or merely *detected something*.
There may be some more work required here.
2. This experiment *cannot* be generalized to mathematically predict and
experimentally measure frequency modulation due to Doppler shifts *through a
loudspeaker*. Note that the experiment doesn't mention this generalization;
it does not discuss loudspeakers at all. The linear motor does *not* radiate
the low frequency as sound waves, as a loudspeaker does. This completely
changes the dynamics of the situation in terms of the motion of the
radiators and the transfer of energy into the surrounding air.
3. To have any relevance to audio reproduction through loudspeakers, this
experiment needs to be repeated to mathematically predict, and then, *using
a loudspeaker*, experimentally measure frequency modulation due to Doppler
shifts.
4. For either experiment, it is not sufficient to simply *detect* FM
sidebands. The frequencies, amplitudes and phases obtained experimentally
must agree closely with the values predicted mathematically.
The Ghost
> "The Ghost" <the_gho...@netzero.com> wrote in message
> news:b5fb78ba.04081...@posting.google.com...
> > THE HYPOTHESIS:
> > Assuming that the.....
> > THE SETUP:
> > A small circular piezoelectric bimorph.......
> > THE MOTION OF THE SOUND SOURCE
> > A triangular command signal.........
> > THE MEASUREMENT RESULT
> > The propagating 10KHz signal.......
> > THE CHALLENGE
> > In science, theory usually follows.........
> 1. I believe this experiment is relevant in that we should be able to
> mathematically predict and experimentally measure frequency modulation due
> to Doppler shifts with a good degree of agreement within the constraints
> this setup (i.e., a linear motor pushing a peizo radiator back and forth).
> It is not clear whether the OP was able to correlate the experimental
> results with the mathematical predictions, or merely *detected something*.
> There may be some more work required here.
You are correct. You should be able to mathematically model the
experiment and predict the experimental result, but I am not going to
do it for you. Also, the measurement didn't just merely detect
"something." The measurement demonstrated that motional information
about the periodic trapezoidal velocity the peizo element exists in
the FM sidebands of the 10KHz propagating carrier and that the FM
demodulated signal had the same trapezoidal shape as the velocity of
the shaft of the linear motor. This result is exactly what is
predicted qualitatively by a phenomenological model of dynamic Doppler
shift. This experimental result is difficult, if not impossible, to
explain on the basis of IM distortion because there is no readily
identifiable nonlinear mechanism that is common to both the
low-frequency motion of the shaft and the high frequency motion of the
piezo element. The measurement results provide a very strong
counter-argument against those claiming that dynamic Doppler shift
does not exist. That was the sole purpose of measurement. If you or
anyone else wishes to carry it to the next "quantative" level, please
be my guest.
> 2. This experiment *cannot* be generalized to mathematically predict and
> experimentally measure frequency modulation due to Doppler shifts *through a
> loudspeaker*. Note that the experiment doesn't mention this generalization;
> it does not discuss loudspeakers at all.
That is correct, unless you can find a loudspeaker that produces
negligible IM distortion so that the propagating energy in the
sidebands is predominantly the result of dynamic Doppler shift and not
the result of IM in the actual cone vibration itself.
>The linear motor does *not* radiate
> the low frequency as sound waves, as a loudspeaker does. This completely
> changes the dynamics of the situation in terms of the motion of the
> radiators and the transfer of energy into the surrounding air.
That is incorrect. The surface of the piezo element radiates the low
frequency motion of the motor shaft, but that radiation is very low
because the frequency is low and because the surface area of the piezo
element is small. Furthermore, the amount of low-frequency sound that
is radiated is irrelevent to the issue of the production of dynamic
Doppler shift.
> 3. To have any relevance to audio reproduction through loudspeakers, this
> experiment needs to be repeated to mathematically predict, and then, *using
> a loudspeaker*, experimentally measure frequency modulation due to Doppler
> shifts.
Because of the existence of IM, the mathematical model will have to
take into account both the radiation of IM products as well as the
dynamic Doppler shift, since both contribute sideband energy at the
same frequencies. If you are prepared to take on that task, all I can
do is wish you luck.
> 4. For either experiment, it is not sufficient to simply *detect* FM
> sidebands. The frequencies, amplitudes and phases obtained experimentally
> must agree closely with the values predicted mathematically.
Amplitudes and phase information needs to be preserved, but in the
case of my experiment, no mathematical prediction is necessary. I
used a trapezoidal instead of sinusoidal velocity of the shaft linear
motor specifically to get around the need for a mathematical
prediction. Because the velocity of the linear motor was
non-sinusoidal, the information in the sidebands needs to be accurate
only in terms of relative amplitude and relative phase. The
non-sinusoidal velocity information will be preserved in the
sidebands, and appear at the output of the FM demodulator, only if the
relative ampliude and relative phase information is correctly
preserved in the sidebands of the radiated signal.
Karl Uppiano
That's why my initial reaction to your experiment was positive. My mistake
(and others also) was in jumping to the conclusion that your results could
be applied directly to Doppler FM in a loudspeaker. It cannot, and you never
claimed they could, which is a "Good Thing".
>> 2. This experiment *cannot* be generalized to mathematically predict and
>> experimentally measure frequency modulation due to Doppler shifts
>> *through a
>> loudspeaker*. Note that the experiment doesn't mention this
>> generalization;
>> it does not discuss loudspeakers at all.
>
> That is correct, unless you can find a loudspeaker that produces
> negligible IM distortion so that the propagating energy in the
> sidebands is predominantly the result of dynamic Doppler shift and not
> the result of IM in the actual cone vibration itself.
Unfortunately, that's true. AM and FM sidebands look fairly similar at low
FM modulation indices. They might be hard to distinguish, although IIRC,
upper and lower FM sidebands are opposite in phase.
>>The linear motor does *not* radiate
>> the low frequency as sound waves, as a loudspeaker does. This completely
>> changes the dynamics of the situation in terms of the motion of the
>> radiators and the transfer of energy into the surrounding air.
>
> That is incorrect. The surface of the piezo element radiates the low
> frequency motion of the motor shaft, but that radiation is very low
> because the frequency is low and because the surface area of the piezo
> element is small. Furthermore, the amount of low-frequency sound that
> is radiated is irrelevent to the issue of the production of dynamic
> Doppler shift.
The low frequency radiation is much less efficient for the reasons you
state. A loudspeaker, on the other hand, radiates all frequencies in its
usable frequency range with nominally equal efficiency. That is not the case
with your experimental setup, as you point out.
I not only believe that it is not only relevant, *but crucial* whether the
low frequency component is radiated, to the issue of dynamic Doppler shift.
The entire energy equation changes. Instead of a high frequency sound source
moving back and forth in free air, we are instead summing two acoustic
waves. It's entirely different.
>> 3. To have any relevance to audio reproduction through loudspeakers, this
>> experiment needs to be repeated to mathematically predict, and then,
>> *using
>> a loudspeaker*, experimentally measure frequency modulation due to
>> Doppler
>> shifts.
>
> Because of the existence of IM, the mathematical model will have to
> take into account both the radiation of IM products as well as the
> dynamic Doppler shift, since both contribute sideband energy at the
> same frequencies. If you are prepared to take on that task, all I can
> do is wish you luck.
I'm afraid I don't have the time or the equipment. I'm just suggesting the
need for further research if anyone is really interested in proving or
disproving the existence of Doppler FM in loudspeakers. This is where a
prediction from a mathematical model is important. It isn't sufficient to
get a louspeaker to produce something that "smells like Doppler FM". You
need a model that predicts how much, at what freqencies, in what phase,
etc., and then you need to get good experimental agreement with your
prediction. Otherwise, you could be measuring anything -- other forms of
distortion, environmental noise, sampling errors, etc. In the end, it must
all be accounted for if it's the *truth* you're looking for. Unsubstantiated
claims are much less demanding :-)
>> 4. For either experiment, it is not sufficient to simply *detect* FM
>> sidebands. The frequencies, amplitudes and phases obtained experimentally
>> must agree closely with the values predicted mathematically.
>
> Amplitudes and phase information needs to be preserved, but in the
> case of my experiment, no mathematical prediction is necessary. I
> used a trapezoidal instead of sinusoidal velocity of the shaft linear
> motor specifically to get around the need for a mathematical
> prediction. Because the velocity of the linear motor was
> non-sinusoidal, the information in the sidebands needs to be accurate
> only in terms of relative amplitude and relative phase. The
> non-sinusoidal velocity information will be preserved in the
> sidebands, and appear at the output of the FM demodulator, only if the
> relative ampliude and relative phase information is correctly
> preserved in the sidebands of the radiated signal.
I believe prediction *is* necessary. You did predict some things, and you
were able to experimentally bear out your predictions. But if you had
predicted trapezoidal FM with a slope x, and you measured sinusoidal FM with
a maximum slope of -2x, I'd say your predictions, or your measurements were
off. You haven't proved anything until you have a high degree of agreement
between your prediction and your measured results, and you can account for
any remaining errors to the satisfaction of all reviewers. That's what's
meant by "reproducible results".
Bob Cain
The Ghost wrote:
>>The linear motor does *not* radiate
>>the low frequency as sound waves, as a loudspeaker does. This completely
>>changes the dynamics of the situation in terms of the motion of the
>>radiators and the transfer of energy into the surrounding air.
>
>
> That is incorrect. The surface of the piezo element radiates the low
> frequency motion of the motor shaft, but that radiation is very low
> because the frequency is low and because the surface area of the piezo
> element is small. Furthermore, the amount of low-frequency sound that
> is radiated is irrelevent to the issue of the production of dynamic
> Doppler shift.
He was correct and you are not. It is entirely a matter of
the frequency dependant coupling.
I know, I know. You could prove otherwise but won't.
The Ghost
> That's why my initial reaction to your experiment was positive. My mistake
> (and others also) was in jumping to the conclusion that your results could
> be applied directly to Doppler FM in a loudspeaker. It cannot, and you never
> claimed they could, which is a "Good Thing".
My measurement results can be applied to a loudspeaker but only to the
extent that they demonstrate that dynamic Doppler shift can be
produced by a loudspeaker. Whether or not Doppler shift produced by a
loudspeaker can be measured is another issue. That is going to depend
on the relative amount of intermodulation distortion that the
loudspeaker also produces because the Doppler FM components and the
intermodulation distortion components are at the same frequencies.
Personally, I wouldn't waste my time trying to separate the two.
> ................... AM and FM sidebands look fairly similar at low
> FM modulation indices. They might be hard to distinguish, although IIRC,
> upper and lower FM sidebands are opposite in phase.
The FM demodulator that I used was a precision frequency-to-voltage
converter which operates on zero crossings and, as such, is completely
insensitive to amplitude variations of the signal being demodulated.
> The low frequency radiation is much less efficient for the reasons you
> state. A loudspeaker, on the other hand, radiates all frequencies in its
> usable frequency range with nominally equal efficiency. That is not the case
> with your experimental setup, as you point out.
> I not only believe that it is not only relevant, *but crucial* whether the
> low frequency component is radiated, to the issue of dynamic Doppler shift.
> The entire energy equation changes. Instead of a high frequency sound source
> moving back and forth in free air, we are instead summing two acoustic
> waves. It's entirely different.
>.............. It isn't sufficient to
> get a louspeaker to produce something that "smells like Doppler FM". You
> need a model that predicts how much, at what freqencies, in what phase,
> etc., and then you need to get good experimental agreement with your
> prediction. Otherwise, you could be measuring anything -- other forms of
> distortion, environmental noise, sampling errors, etc. In the end, it must
> all be accounted for if it's the *truth* you're looking for. Unsubstantiated
> claims are much less demanding :-)
Not surprisingly, we again mostly disagree. In the early stages of
research, where the issue is whether or not a phenomenon exists, the
first order of business is to demonstrate experimentally the existence
of the phenomenon. After the existence of the phenomenon has been
demonstrated, model development and quantative predictions follow.
For whatever reason, you seem to refuse to distinguish between the
existence of a phenomenon and the accurate quantitative description of
a phenomenon. The absence of a quantitative description of a
phenomenon is not a justifiable excuse for denying its existence. In
the history of science, there are many phenomena that were
demonstrated first and quantified later.
> You haven't proved anything until you have a high degree of agreement
> between your prediction and your measured results, and you can account for
> any remaining errors to the satisfaction of all reviewers. That's what's
> meant by "reproducible results".
If you believe that, then you have a lot to learn. It has been my
experience over many years that models go up in flames, more often
than not, becasue of fundamental phenomenological
inconsistencies/inadequacies rather than because they did not produce
a sufficiently high degree of agreement between prediction and
measured results.
Bob Cain
The Ghost wrote:
> Not surprisingly, we again mostly disagree. In the early stages of
> research, where the issue is whether or not a phenomenon exists, the
> first order of business is to demonstrate experimentally the existence
> of the phenomenon. After the existence of the phenomenon has been
> demonstrated, model development and quantative predictions follow.
> For whatever reason, you seem to refuse to distinguish between the
> existence of a phenomenon and the accurate quantitative description of
> a phenomenon. The absence of a quantitative description of a
> phenomenon is not a justifiable excuse for denying its existence. In
> the history of science, there are many phenomena that were
> demonstrated first and quantified later.
Evidence for existence of a phenomenon requires elimination
of spurious causes one way or another, either by
experimental setup or by having a _good_ characterization of
the spurious phenomena so that their effect can be removed
from the test data. How does your "experiment" do either so
that what remains can be legitimately regarded as evidence
of Doppler distortion?
And even if it satisfied that requirement, the phenomenon in
question now is not simply Doppler distortion but the
mechanism that produces it so a predictive model is
absolutely required. Why, if the mechanism is as simple as
is described, has no such model been forthcoming?
This is basic stuff and should not have to be spoon fed to
anyone who claims to be an experimental scientist.
Ben Bradley
In
alt.music.home-studio,rec.audio.tech,rec.audio.pro,alt.sci.physics.acoustics
On Mon, 23 Aug 2004 18:55:28 -0700, Bob Cain
<arc...@arcanemethods.com> wrote:
>
>
>The Ghost wrote:
>
>> Not surprisingly, we again mostly disagree. In the early stages of
>> research, where the issue is whether or not a phenomenon exists, the
>> first order of business is to demonstrate experimentally the existence
>> of the phenomenon. After the existence of the phenomenon has been
>> demonstrated, model development and quantative predictions follow.
>> For whatever reason, you seem to refuse to distinguish between the
>> existence of a phenomenon and the accurate quantitative description of
>> a phenomenon. The absence of a quantitative description of a
>> phenomenon is not a justifiable excuse for denying its existence. In
>> the history of science, there are many phenomena that were
>> demonstrated first and quantified later.
>
>Evidence for existence of a phenomenon requires elimination
>of spurious causes one way or another, either by
>experimental setup or by having a _good_ characterization of
>the spurious phenomena so that their effect can be removed
>from the test data.
How would something cause the doppler effect? By emitting sound and
moving relative to a receiver. What is moving (and emitting sound) in
the systems we have been describing? Voice coil, cone, spider,
surround. Of these, perhaps the surround could cause spurious doppler
effect (because it's moving, but "on average" it moves only half as
fast and half as far as the cone). It also has much less radiating
area than the cone. I'm not even considering the spider and voice
coil, because not only do they not offer much surface area, they're
not facing forward and aren't 'visible' through the cone. There's also
the dust cap, but it is considered part of the cone.
You could argue the speaker frame moves in response to the cone's
movement (Newton's Nth law of motion, I forget what N is), but that
can be reduced substantially by securely mounting the driver on a
large concrete block, effectively increasing its mass and lowering its
movement.
>How does your "experiment" do either so
>that what remains can be legitimately regarded as evidence
>of Doppler distortion?
>
>And even if it satisfied that requirement, the phenomenon in
>question now is not simply Doppler distortion but the
>mechanism that produces it so a predictive model is
>absolutely required. Why, if the mechanism is as simple as
>is described, has no such model been forthcoming?
>
>This is basic stuff and should not have to be spoon fed to
>anyone who claims to be an experimental scientist.
Yes, Bob, it IS basic stuff.
The speed of sound at sea level is about 1116 feet per second
(google). A 1kHz tone has a wavelenth of 1.116 feet (or 1 foot, 1.32
inches). Run a 1kHz tone from a signal generator into both an
oscilloscope (channel 1, trigger on channel 1) and an audio amplifier
that drives a speaker. Put a microphone a couple of feet from the
speaker, run its output through a preamp (or directly) to channel 2 of
the oscilloscope. Adjust vertical gains appropriately to get a good
vertical displacement of each sine wave. You should be able, by
changing the distance from the microphone to the speaker, put these
two sine waves in phase. If you increase the distance between the mic
and speaker, the bottom (channel 2) trace should go through a whole
cycle when the distance changes by 1 foot and 1.32 inches.
Mount the speaker on a shaker table, and program it to do various
movements (changing the distance between it and the mic) at various
speeds. Observe the scope traces while this is happening. The bottom
trace shows a phase change that corresponds exactly and instantly
(less a small amount of latency caused by the speed of sound) to the
motion of the speaker, or more specifically, the distance between it
and the mic.
Mix (in the audio, additive sense, not the radio/RF,
multiplicative/nonlinear sense) a low-frequency (0.1 Hz to 50 Hz)
signal with the 1kHz tone so that they both are amplified and drive
the speaker. This causes cone motion (assuming it stays within the
linear range of the driver), but the 1kHz signal is still emitted from
the speaker. Observe the trace on channel 2, it will show a small
amount of phase shift that directly follows the cone motion. Assuming
1/2 inch peak-to-peak cone excursion, the shift in degrees will be
360*(0.5/12)/1.116=13 degrees. This is not a lot, but you should be
able to increase both the trace speed (shorter timebase) and the
vertical gain for channel 2, and see a diagonal line (if not visible,
move the mic until itiis) that moves back and forth with the speaker
cone. This movement directly follows the cone motion (which in this
case is caused by the low-frequency driving signal), just as it did
when the speaker was on the shaker table.
Bob, I expect you believe the shaker table description, so you
shouldn't have to actually do it. But I would hope you do the
description in the last paragraph. I presume you have the equipment to
do it and know how to wire it up. You should be able to see the phase
change of the 1kHz signal, and IIRC the derivative of the phase change
is frequency change. So if the cone moves (actually accelerates or
decelerates) a visible distance, it will happen. It doesn't matter if
it's below (the cone's free-air) resonance or above resonance, if it
moves visibly, it's enough to cause measurable phase shift and thus
frequency modulation.
>Bob
I can suggest some sauce for your hat, it's Mezzetta's Habanero
sauce with the appropriate words "Twist and Shout" on the label. It's
definitely up there on the heat scale, but not as concentrated as the
"Hell Hot" sauce which seems to have a lot of radioactive byproducts.
Mezzetta's has a touch of sweet (?) taste along with the hot flavor,
while others of just have the hot flavor piled on top of the hot
flavor. Putting a teaspoon or two on the edge of your plate and adding
a small bit to each bite can add that extra flavor to even the
toughest dishes.
Bob Cain
Ben Bradley wrote:
> Bob, I expect you believe the shaker table description, so you
> shouldn't have to actually do it.
Ben, you may not have seen it in my posts for the last week
or so but I am no longer disputing that a Doppler distortion
phenomeon exists and that your experiment would show it even
with ideal speakers. It's patently obvious from the thought
experiment of a speaker on a long swing emitting a tone.
Where I remain in divergence from the mainstream is the
cause of it. I do not believe that if you were to do the
two tone experiment with a clean piston in a tube such that
the boundry conditions enforce the creation of a plane wave,
that you would see any Doppler distortion. Mainstream
thinking says you would. The reason it doesn't is that the
coupling of speaker to a distant receiver is a constant,
frequency independant function in that case. I say that
mixing does not occur at the piston/air interface but
further out in the radiated field instead.
What I am disputing at this point is the mechanism. It does
not occur because of little fast waves riding on big slow
ones in the cone but rather under circumstances where the
coupling from speaker to detector is frequency dependant. A
speaker in a box has a very frequency dependant coupling
to the far field and will evidence Doppler distortion.
An ESL in a push-pull configuration is a very low distortion
emitter and has the advantage that the diapragm motion can
be very accurately measured by incuding the capacitance
between the diaphragm an one of the push-pull plates in a
tuned RF modulator. An FM detector on that RF signal will
quite accurately tell what the diaphragm is actually doing
so as to provide a reference signal for any experiment.
I predict that such a system will show no Doppler distortion
in a tube if one can be constructed. The requisite
terminations at the ends is probably too difficult, however.
If it is too difficult, the ESL can be used free standing
for a different experiment. If the principle of my theory
of what causes Doppler distortion is correct, the amount of
it will increase relative to the signal as you distance
yourself from the speaker if the low frequency used in the
experiment is low enough that its coupling to the receiver
decreases much more rapidly with distance than the high
frequency one. The principle I am trying to refute would
make the amount of distortion relative to the signal
independant of the receiver position in space.
>
> I can suggest some sauce for your hat, it's Mezzetta's Habanero
> sauce with the appropriate words "Twist and Shout" on the label. It's
> definitely up there on the heat scale, but not as concentrated as the
> "Hell Hot" sauce which seems to have a lot of radioactive byproducts.
> Mezzetta's has a touch of sweet (?) taste along with the hot flavor,
> while others of just have the hot flavor piled on top of the hot
> flavor. Putting a teaspoon or two on the edge of your plate and adding
> a small bit to each bite can add that extra flavor to even the
> toughest dishes.
I will definitely save that recipe should either solid
experiment or theory refute the principle on which I think
an accurate theory can be based. :-)
Without a full development of either, I've shown how the
predictions of mine and the popular one will differ with a
fairly easy experiment to set up and do (as experiments go.)
Wish I could do it myself but I have neither the resources
nor the available time.
I still haven't seen any attempt at all to refute the
argument which says it can't exist with a piston in a tube
because of the principle of reciprocity. Several have
hollered that reciprocity doesn't apply to pistons driving
air but without a single detailed reason why not without
appeal to sound pressures that yield a signifigantly
non-linear relationship between pressure and velocity.
Porky
I agree with everything you've said, except that it doesn't apply to
loudspeakers, you've just come up with a fancier variation of the
train/whistle model, which doesn't apply to speakers because the speaker is
reproducing a complex soundwave in toto from a single complex driving
source, what you're doing is the same as picking up the speaker and moving
it back and forth and that will certainly produce Doppler shift. It isn't
that the motion is dynamic, it's that the motion is coming from a single
source which producing a complex sound, that is the reason a speaker doesn't
produce doppler shift when reproducing music.
Mark
> He was correct and you are not. It is entirely a matter of
> the frequency dependant coupling.
>
Bob,
If you set up your coupling tube so that the speaker cone pushes the
air completly and the air moves in the tube without loss and at the
far end the air pushes the mic diaphram completly SO THAT THE SPEKAER
CONE AND MIC DIPHRAM ARE MOVING TOGETHER IN LOCK STEP WITH THE SAME
DISPLACEMENT, then you are correct, there is no Doppler effect. Note
that in this case the distance between the Rx and Tx is constant and
there is no Doppler effect.
In any other case where the mic diaphram is not moving in lock step
with the cone, there will be a Doppler effect.
Mark
The Ghost
> The Ghost wrote:
>
> > ......... The absence of a quantitative description of a
> > phenomenon is not a justifiable excuse for denying its existence. In
> > the history of science, there are many phenomena that were
> > demonstrated first and quantified later.
> Evidence for existence of a phenomenon requires elimination
> of spurious causes one way or another, either by
> experimental setup or by having a _good_ characterization of
> the spurious phenomena so that their effect can be removed
> from the test data. How does your "experiment" do either so
> that what remains can be legitimately regarded as evidence
> of Doppler distortion?
I contend that my experiment has no so-called spurious phenomena.
Since you are the one claiming that it does, it is your responsibility
to identify them and demonstrate, with your own measurements, that my
measurement results are invalidated when the so-called spurious
phenomena are removed. Given that my measurement result agree with
expectation that the instantaneous FM-demodulated propagating signal
follows in time the instantaneous trapezoidal velocity of the source,
I seen no need to go looking for so-called spurious phenomena which
exist only in your mind.
> And even if it satisfied that requirement, the phenomenon in
> question now is not simply Doppler distortion but the
> mechanism that produces it so a predictive model is
> absolutely required. Why, if the mechanism is as simple as
> is described, has no such model been forthcoming?
The mechanism for instantaneous Doppler shift is instantaneous
relative motion between the source and the observer. Beyond that, any
predictive model would necessarily have to be situation specific, and
in that regard, the simplest situations to model are the most
difficult to experimentally verify and vice versa.
> This is basic stuff and should not have to be spoon fed to
> anyone who claims to be an experimental scientist.
It is you, not I, who is having problems understianding this basic
stuff.
Bob Cain
Mark wrote:
>
> If you set up your coupling tube so that the speaker cone pushes the
> air completly and the air moves in the tube without loss and at the
> far end the air pushes the mic diaphram completly SO THAT THE SPEKAER
> CONE AND MIC DIPHRAM ARE MOVING TOGETHER IN LOCK STEP WITH THE SAME
> DISPLACEMENT, then you are correct, there is no Doppler effect.
Yes, exactly. And if they aren't I'd like to be shown why,
exactly and without any unparamaterized or underived
formulas. All axioms should be stated for purposes of
criticism and a derivation proceed from there to a proof
that reciprocity fails in this case. Because if it doesn't,
then if you make the active piston passive and measure
motion due to passage of a wave (coming from the side of it
opposite the receiver) and then make the piston active to
generate the same motion, the reciever at the end will see
two different things. I don't believe it.
I really don't expect any of my opponents in this debate to
address this because it seems they never do if they can't
explain it and then it remains invalid by their silence as
if it had never been uttered.
The Ghost
> If you set up your coupling tube so that the speaker cone pushes the
> air completly and the air moves in the tube without loss and at the
> far end the air pushes the mic diaphram completly SO THAT THE SPEKAER
> CONE AND MIC DIPHRAM ARE MOVING TOGETHER IN LOCK STEP WITH THE SAME
> DISPLACEMENT, then you are correct, there is no Doppler effect. Note
> that in this case the distance between the Rx and Tx is constant and
> there is no Doppler effect.
>
> In any other case where the mic diaphram is not moving in lock step
> with the cone, there will be a Doppler effect.
Your assessment is correct, but not exactly for the reason you state.
The only way the transmitter and receiver can move in lock step is if
the propagation time is zero; and the only way that the propagation
time can be zero is if the sound velocity in the medium is infinite.
Of course, this is exactly what the Doppler equation,
fr/fs=1/(1-(vs/c)), predicts. For c-->infinity, fr=fs.
Contrary to Bob Cain's false and unsubstantiated belief, dynamic
Doppler shift does occur in a tube, and a direct measurement of it
will be forthcoming.
The Ghost
> I agree with everything you've said, except that it doesn't apply to
> loudspeakers, you've just come up with a fancier variation of the
> train/whistle model, which doesn't apply to speakers because the speaker is
> reproducing a complex soundwave in toto from a single complex driving
> source, what you're doing is the same as picking up the speaker and moving
> it back and forth and that will certainly produce Doppler shift. It isn't
> that the motion is dynamic, it's that the motion is coming from a single
> source which producing a complex sound, that is the reason a speaker doesn't
> produce doppler shift when reproducing music.
Since you fail to see the clear and obvious equivalence and relevance,
all I can say is that you are an idiot.
Mark
Interesting,
If the Tx is vibrating at 50 Hz and 4 kHz, and the couling through
the tube is complete and lossless then the Rx cone will move with the
same displacement. You are correct and I take your point regarding
the prop delay. So the cones may not be in lock step due to the prop
delay and the relative motion due to the 50 Hz cone vibrations which
are not in phase may create Doppler to the 4 kHz...I agree.
But consider a SPECIAL CASE, where the distance from Rx to Tx is such
that the prop delay equals an integer number of wavelengths of 50Hz,
then the cones will be in lock step at 50 Hz. So perhaps the correct
answer for this special 100% coupled tube case, is that the Doppler is
a critical function of the distance between the Rx and Tx.
This is a very pathalogical case anyway. In nearly any real
situation, the Rx and Tx cones will not be in lock step so the
distance from Rx to Tx will be changing and Doppler will occur.
Mark
The Ghost
> But consider a SPECIAL CASE, where the distance from Rx to Tx is such
> that the prop delay equals an integer number of wavelengths of 50Hz,
> then the cones will be in lock step at 50 Hz. So perhaps the correct
> answer for this special 100% coupled tube case, is that the Doppler is
> a critical function of the distance between the Rx and Tx.
It is not good to use imprecise non-technical terminology. In that
regard I am guilty of following your lead, but only because I thought
we were referring to the same thing. For Doppler shift not to exist,
the propagation delay needs to be zero. But zero time delay is not
the same as zero phase shfit. In the sinusoidal steady state, it is
not only possible but quite common for two waveforms to be in phase
even though there is a significant time delay between them. In order
to avoid the confusion, you should think of what is happening in terms
of transient signals such as a pulse or short tone burst instead of
sinusoidal steady state signals.
Bob Cain
The Ghost wrote:
> For Doppler shift not to exist,
> the propagation delay needs to be zero. But zero time delay is not
> the same as zero phase shfit.
Doppler mixing occurs if and only if the coupling from Tx to
Rx is frequency dependant. If it is independant, the
distance between Tx and Rx, so long as it is fixed, is
irrelevant. It won't happen with a piston in a terminated
tube.
Bob Cain
Bob Cain wrote:
>
>
> The Ghost wrote:
>
>> For Doppler shift not to exist,
>> the propagation delay needs to be zero. But zero time delay is not
>> the same as zero phase shfit.
>
>
> Doppler mixing occurs if and only if the coupling from Tx to Rx is
> frequency dependant. If it is independant, the distance between Tx and
> Rx, so long as it is fixed, is irrelevant. It won't happen with a
> piston in a terminated tube.
>
>
> Bob
As a quasi-final note with respect to this whole dispute I'd
like to quote to this crossposted thread a response I just
gave Jim Carr to a post that was only in
alt.music.home-studio. This is all I've got to say until a
lot more has matured.
Jim Carr wrote:
> Bob,
>
[compliment snipped]
> ... it looks like you're growing weary and a bit
> irritable, so maybe you might want to drop it.
Yes, I have grown weary and irritable with respect to the ad
hominem crap, as well as utterly convinced that the correct
principle for Doppler mixing is that of frequency dependant
coupling between Tx and Rx. What remains to be done is to
take that principle to a full theory. That may not be at
all easy because it will be a field theory and they are
notoriously difficult to formulate from the principle on
which they are based.
If and when that theory is complete and boundry conditions
are imposed and the differential equations are solved, if
they are solvable, then we will have something predictive.
The common equation for Doppler shift will fall out of one
boundry condition, relative velocity of Rx relative to Tx
being static rather than dynamic. Even that will only be
valid for a single frequency under general conditions.
> You'll probably never get what you want. I haven't seen
> anyone post a formula that says, "If I put out a 50Hz tone
> and a 1200Hz tone from a speaker with an excursion of 3mm
> I will expect to see ..." and then follow it up with an
> experiment that showed the predicted results and provided
> a way to eliminate spurious information. I doubt anyone
> will come through at this point.
Nor will anyone from any theory that uses the static Doppler
shift equation as its basic principle.
> Those rec.audio.pro guys can get pretty arrogant and
> nasty.
Yeah, I'm one of them. :-)
> I haven't seen that much blustering since the Blizzard of
> '79! If it were me I'd just take my ball and go home.
>
> Anyway, not everyone here thinks you're an arrogant,
> ignorant asshole. Well, at least not all three at once.
_LOL!_ My ball with regard to Doppler mixing is the
principle of frequency dependant coupling between Tx and Rx
and I will indeed take it home until I or I and a
collaborator who is facile with the necessasary math toolkit
(div, grad, curl, infinitessimal volumes, and other vector
calculus methods) can return with a fleshed out theory from
first principles. I am confident that can be done but far
less confident that I can do it.
Thanks,
The Ghost
> The Ghost wrote:
>
> > For Doppler shift not to exist,
> > the propagation delay needs to be zero. But zero time delay is not
> > the same as zero phase shfit.
>
> Doppler mixing occurs if and only if the coupling from Tx to
> Rx is frequency dependant. If it is independant, the
> distance between Tx and Rx, so long as it is fixed, is
> irrelevant. It won't happen with a piston in a terminated
> tube.
umsubstantiated beliefs.
Bob Cain
The Ghost wrote:
>>Doppler mixing occurs if and only if the coupling from Tx to
>>Rx is frequency dependant. If it is independant, the
>>distance between Tx and Rx, so long as it is fixed, is
>>irrelevant. It won't happen with a piston in a terminated
>>tube.
>
>
> And that is nothing more than another one of your nonsensical,
> umsubstantiated beliefs.
Then it should be quite easy for you to formally refute it.
Have at it. Yeah, right. You're a washed up antisocial
who once, long ago, did some hearing research with someone
who actually was important but you've been isolated by your
sociopathy to where your rage is all you have left and it
simply reflects what you think you should have been but for
all the idiots. You can use tables to give the answers to
problems that have been solved by others but have no
understanding at all below that level. You also seem
incapable of learning.
If that's wrong, prove otherwise with an actual display of
any technical acumen. I can't figure out why you are even
on usenet. You have nothing whatsoever to contribute other
than insults that would get your head torn off with shit
down the remaining food pipe were you to deliver them face
to face. Probably why you're afraid to leave your room.
If you can show you actually know anything by giving a
logical proof of your theory with all axioms clearly stated
and available for challenge and all non-axiomatic formulae
dependant only on what has been already formally derived and
with all constants and variables given precise physical
meaning, I'll bow down before you. I can't see why such a
thing should even be a challenge to one such as yourself.
Or rage on, asshole, because that's all anyone expects from
you anyway.
Your "experiments" if you actually have performed any are
such kludges that nothing at all can be concluded from them.
They show an utter disregard for science, or more likely
no understanding of what science is.
I know one of your couple of sock puppets will step up to
defend you and tell us that they know you really are an
expert but that's pretty transparent by now.
Sorry to take the gloves off in front of everybody else but
I do feel a whole lot better after telling it like it is.
I took alt.sci.physics.acoustics off this because they are
all much too polite for such a reality check. You'll
probably re-post it there anyway looking for sympathy.
The Ghost
> Yes, I have grown weary and irritable with respect to the ad
> hominem crap,......
Excuse me while I reach for an air sickness bag, you pathetic and
contemptable piece of human waste. After all of the ad hominem
attacks that you have bestowed upon me recently, and over the last 3-4
years, you are now whining about the so-called "ad hominem" crap.
> .......as well as utterly convinced that the correct
> principle for Doppler mixing is that of frequency dependant
> coupling between Tx and Rx.
That is utter nonsensical drivel.
> What remains to be done is to take that principle to a full theory.
The only thing that remains to be done is to discredit you entirely on
the issue of dynamic Doppler shift/distiortion. As you well know,
that is in process. It is baout time that you confront reality and
admit that you have been wrong about every aspect of this issue.
> > Anyway, not everyone here thinks you're an arrogant,
> > ignorant asshole. Well, at least not all three at once.
Yes, all three at once. And, anyone who doesn't is either in bed with
this scumbag is brain dead (my unbiased opinion, of course).
> _LOL!_ My ball with regard to Doppler mixing is the
> principle of frequency dependant coupling between Tx and Rx
> and I will indeed take it home until I or I and a
> collaborator who is facile with the necessasary math toolkit
> (div, grad, curl, infinitessimal volumes, and other vector
> calculus methods) can return with a fleshed out theory from
> first principles. I am confident that can be done but far
> less confident that I can do it.
At least you are right about one thing...you can't do it. And, since
your so-called Doppler-mixing principle is nothing more than
nonsensical drivel, neither can anyone else.
Lastly, the only thing that you have grown weary about is the fact
that your denial of dynamic Doppler shift in a tube has just been
proven wrong.....and you know it. The theoretical analysis shows that
dynamic Doppler shift does in fact exist in a tube. Direct
measurements, confirming the theoretical analysis, will also be
forthcoming. Bottom line, all of your unsubstantiated, mindless
beliefs have been proven wrong and you have been discredited.....and
you know it. But, rather than stand up like a man and admit it, you
would like everone to believe that you have simply "grown weary and
irritable." Please excuse me while I reach for another air sickness
bag.
Bob Cain
The Ghost wrote:
> Lastly, the only thing that you have grown weary about is the fact
> that your denial of dynamic Doppler shift in a tube has just been
> proven wrong.....and you know it.
Nonsense. Prove its existence and its precise predictions
on paper or shut up. You can't. You do know what a proof
entails, right? All your crude posturing means absolutely
nothing in light of your inability to do that. Give us a
reason for your certainty that has a tad more credibility
than your hateful spew. State your axioms so that their
validity can be subject to verificaion and challenge; from
them formally derive equations that rely on nothing but the
axioms and equations already derived; define in precise
physical terms what every variable and constant is and end
up with an equation that precisely describes the effect.
Two tones, one dimensinal analysis will do if a more general
treatment escapes your razor sharp mind. You know the
routine. Or do you? At one time aquiring a Ph.D. in
anything technical required facility in that kind of proof.
Falling back on your posture that you don't spoon feed the
peanut gallery just won't do this time. You are in deep
enough with this that your reputation is on the line. If
you can't or won't prove your assertions, nothing you say
from here on out about anything has a lick of credibility.
Your experiments, if you have actually done any, are such
kludges that they disclose nothing of the source of dynamic
Doppler mixing.
You know what you must do now and I have nothing further to
say to you until you have done it or shown the intellectual
honesty to disclose the false assumption in your theory.
Should you succeed and should your proof stand up I will be
the first to acknowlege your skill at doing something that
has not been done before and I will do that as many places
as this debate has raged in no uncertain terms. A diet of
crow bothers me not in the least if something useful is
accomplished along the way.
I too will be attempting the same for mine and will shut up
about it until I have accomplished the same kind of proof
that I expect from you.
Until such a proven theory emerges, the whole business of
the source of dynamic Doppler mixing is speculation on all
sides.
The Ghost
> The Ghost wrote:
>
> > Lastly, the only thing that you have grown weary about is the fact
> > that your denial of dynamic Doppler shift in a tube has just been
> > proven wrong.....and you know it.
>
> Nonsense. Prove its existence and its precise predictions
> on paper or shut up. You can't. You do know what a proof
> entails, right? All your crude posturing means absolutely
> nothing in light of your inability to do that. Give us a
> reason for your certainty that has a tad more credibility
> than your hateful spew. State your axioms so that their
> validity can be subject to verificaion and challenge; from
> them formally derive equations that rely on nothing but the
> axioms and equations already derived; define in precise
> physical terms what every variable and constant is and end
> up with an equation that precisely describes the effect.
> Two tones, one dimensinal analysis will do if a more general
> treatment escapes your razor sharp mind. You know the
> routine. Or do you? At one time aquiring a Ph.D. in
> anything technical required facility in that kind of proof.
Bob, you have a big mouth, a small mind and virtually no character.
You know that the idealized analysis of Doppler distortion produced by
a piston in one end of an infinite tube has been done, and you know
that the result disproves your unsubstantiated claim that Doppler
distortion does not exist under such conditions. I know that you know
the results of the analysis becasue I have been copied on email that
you have received regarding this matter. For you to pretend at this
point that you are still right about this issue is about as personally
and intellectually dishonest as it gets. Nothing would give me
greater pleasure right now than to post the personal email that you
have received regarding thiis issue and to expose you for the slime
ball that you are. However, out of respect for the wishes of the
person who has done the analysis, I am not going to do that at this
time. Nonetheless, the analysis, the predictions of the analysis and
the experimental results to confirm the predictions of the analysis
will be presented here in due time. The outcome is known and certain
and you know it, but you are a scumbag and you simply don't have the
character to stand up right now and admit that you are wrong.
> Falling back on your posture that you don't spoon feed the
> peanut gallery just won't do this time. You are in deep
> enough with this that your reputation is on the line. If
> you can't or won't prove your assertions, nothing you say
> from here on out about anything has a lick of credibility.
Please, give me a break with the absurd rhetoric. This is little more
than a side game that I play with you solely for relaxation and
amusement.
> Your experiments, if you have actually done any, are such
> kludges that they disclose nothing of the source of dynamic
> Doppler mixing.
For whatever reason, it seems that all you are able to do is make
outrageous, unsubstantiated assertions. Below is a contrary opinion
from an esteemed member of the acoustics community. He refers to my
experiment as "pure" and challenges you to cite so-called "spurious"
elements that you claimed existed. Naturally, like the technically
inept coward that you are, you dropped that challenge like a hot
potato.
---------------------------------------
Subject: Re: Experimental Evidence for Dynamic Doppler Shift
From: Angelo Campanella <a.camp...@att.net>
Newsgroups: alt.sci.physics.acoustics
Reply-To: a.camp...@att.net
> Bob Cain <arc...@arcanemethods.com> wrote in message news:<cge6j...@enews1.newsguy.com>...
>>Evidence for existence of a phenomenon requires elimination
>>of spurious causes one way or another, either by
>>experimental setup or by having a _good_ characterization of
>>the spurious phenomena so that their effect can be removed
>>from the test data. How does your "experiment" do either so
>>that what remains can be legitimately regarded as evidence
>>of Doppler distortion?
OK. So specify the "spurious" elements in this otherwise pure
experiment. If you cannot cite any, perhaps there aren't any other
than
the nonlinear distortion that occurs in speakers whose voice coil is
swung out of the uniform magnetic field of the magnet system. But that
distortion is readily detected by measuring the 2nd and 3rd harmonic
level (which is not of concern other that it not exist).
------------------------------------
> You know what you must do now and I have nothing further to
> say to you until you have done it or shown the intellectual
> honesty to disclose the false assumption in your theory.
> Should you succeed and should your proof stand up I will be
> the first to acknowlege your skill at doing something that
> has not been done before and I will do that as many places
> as this debate has raged in no uncertain terms. A diet of
> crow bothers me not in the least if something useful is
> accomplished along the way.
I'll believe that when I see it. Given that you already know the
outcome of the analysis of the piston in a tube, I suggest that you
start writing your concession speech right now.
> I too will be attempting the same for mine and will shut up
> about it until I have accomplished the same kind of proof
> that I expect from you.
Shut up please, but otherwise don't waste your time attempting to
fight a battle that you have already lost.
> Until such a proven theory emerges, the whole business of
> the source of dynamic Doppler mixing is speculation on all
> sides.
The theory exists and its confirmation is forthcoming. You just don't
have the personal integrity to admit it.
The Ghost
> The Ghost wrote:
>
> > Lastly, the only thing that you have grown weary about is the fact
> > that your denial of dynamic Doppler shift in a tube has just been
> > proven wrong.....and you know it.
>
> Nonsense. Prove its existence and its precise predictions
> on paper or shut up. You can't. You do know what a proof
> entails, right? All your crude posturing means absolutely
> nothing in light of your inability to do that.
.....additional mindless, nonsensical drivel deleted......
For those who are interested, an exact mathematical analysis of the
Doppler distorton that is produced by a vibrating pistion in a tube
can be found at:
http://www.silcom.com/~aludwig/Physics/Exact_piston/dopdist.htm
Bob Cain has been aware of this all along, but his ego has prevented
him from admitting it.
Randy Yates
I can appreciate anyone who wants to see specifics, especially in a
controversial issue such as this. However, what keeps me from pursuing
this with you further is that I sense in you a higher desire to prove
yourself right than to find out the truth. For example, anytime
someone presents some equation or evidence, you knock it down by
invalidating the assumptions or other details that seem fairly
self-evident. Since, as I stated in another response in this thread
quite some time ago (to which I don't recall getting any responses),
ALL theories rest at some point on assumptions, this kind of dissipative
arguing can go on ad-infinitum.
The goal should be to find out the truth. I'm willing to admit I may
be wrong and examine other evidence. Can you?
--RY
Bob Cain <arc...@arcanemethods.com> writes:
--
% Randy Yates % "My Shangri-la has gone away, fading like
%% Fuquay-Varina, NC % the Beatles on 'Hey Jude'"
%%% 919-577-9882 %
%%%% <ya...@ieee.org> % 'Shangri-La', *A New World Record*, ELO
http://home.earthlink.net/~yatescr
Bob Cain
Randy Yates wrote:
> For example, anytime
> someone presents some equation or evidence, you knock it down by
> invalidating the assumptions or other details that seem fairly
> self-evident.
But that is the whole point. Things that seem self evident
are all too often incorrect on deeper analysis.
> Since, as I stated in another response in this thread
> quite some time ago (to which I don't recall getting any responses),
> ALL theories rest at some point on assumptions, this kind of dissipative
> arguing can go on ad-infinitum.
They rest on axioms that are in fact self evident. That the
Doppler equation for static velocities is applicable to time
varying ones without modification is by no means self
evident. That underpins most arguments for Doppler
distortion and is deserving of proof. Sokolich says it is
so proven in Pierces book. I am awaiting delivery of it now
to see if and how that was actually done.
The other argument for it appeals to the longitudinal nature
of acoustic waves, yet every acoustic case we have looked at
has an EM wave equivalent which gives the same results and
EM is transverse. What's up with that?
I'm no longer trying to determine whether it exists, I was
rather quickly persuaded of that. Now it is about why it
exists and I believe the reasons that have been given are wrong.
>
> The goal should be to find out the truth. I'm willing to admit I may
> be wrong and examine other evidence. Can you?
Does it sound like it yet? I've ordered a book that is said
to prove one of the axioms and Art Ludwig has consented to
engage in the kind of proof I think this deserves and to
enter into discussion with me about its specifics. That he
wishes to continue our discussion several weeks after it
began should indicate that at least he sees a real desire in
me to find and understand the truth as he obviously does
himself. However his in depth analysis turns out I admire
him greatly (and am very grateful) for his willingness to
perform it in public.
OTOH, if all your criticism means is that I haven't agreed
with you then perhaps a look in the mirror is appropriate.
Bob Cain
The Ghost wrote:
> http://www.silcom.com/~aludwig/Physics/Exact_piston/dopdist.htm
>
> Bob Cain has been aware of this all along, but his ego has prevented
> him from admitting it.
He just put it up there today, fool, and you know that
because you were copied on the email I received telling me
about it.
I'll have at it. He told me it is just the type of proof
I'm asking for and if it is and it stands up to criticism,
which he has solicited, then I'm wrong. That process, if I
find anything to question, will occur privately between he
and I. However that resolves, or stalemates, I will report
the result.
I have said nothing about the private correspondence that
has gone on between us because it has been inconclusive.
I am _very_ pleased that Art is willing to engage at a
tecnical level on this.
Randy Yates
> [...]
> Does it sound like it yet? I've ordered a book that is said to prove
> one of the axioms and Art Ludwig has consented to engage in the kind
> of proof I think this deserves and to enter into discussion with me
> about its specifics. That he wishes to continue our discussion
> several weeks after it began should indicate that at least he sees a
> does himself. However his in depth analysis turns out I admire him
> greatly (and am very grateful) for his willingness to perform it in
> public.
I agree - I appreciate what Art is doing as well.
> OTOH, if all your criticism means is that I haven't agreed with you
Not at all, Bob. In fact, I get a charge out of seeing a false belief of
my own get overturned. Makes me realize the universe is even more wondrous
than I thought.
> then perhaps a look in the mirror is appropriate.
As Aerosmith said in a song once, "All those lines in my face getting clearer..."
--
% Randy Yates % "Ticket to the moon, flight leaves here today
%% Fuquay-Varina, NC % from Satellite 2"
%%% 919-577-9882 % 'Ticket To The Moon'
%%%% <ya...@ieee.org> % *Time*, Electric Light Orchestra
http://home.earthlink.net/~yatescr
Porky
"Randy Yates" <ya...@ieee.org> wrote in message
news:fz664s...@ieee.org...
> Bob and the rest of the group still reading this thread,
>
> I can appreciate anyone who wants to see specifics, especially in a
> controversial issue such as this. However, what keeps me from pursuing
> this with you further is that I sense in you a higher desire to prove
> yourself right than to find out the truth. For example, anytime
> someone presents some equation or evidence, you knock it down by
> invalidating the assumptions or other details that seem fairly
> self-evident. Since, as I stated in another response in this thread
> quite some time ago (to which I don't recall getting any responses),
> ALL theories rest at some point on assumptions, this kind of dissipative
> arguing can go on ad-infinitum.
>
> The goal should be to find out the truth. I'm willing to admit I may
> be wrong and examine other evidence. Can you?
>
just that, assumptions:
1) based on the original Doppler equation, which is for constant velocity,
and
2) based on the train/whistle analogy which simply does not hold up with the
speaker producing a complex soundwave.
The problem I see with item (1) is that a speaker's cone motion represents
a continuously varying velocity and direction, which is something not
covered directly by the Doppler equation, and in item (2), the train's
motion affects the whistle by moving it through space, but the whistle's
vibration in producing the sound source affects the train's motion not at
all in any practical way. This can be represented by a speaker with a peizo
transducer mounted at its apex, with the speaker driven by a LF tone, and
the peizo element being driven by a HF tone. The peizo transducer, being
solidly mounted to the cone, travels back and forth with it, but the peizo
element's vibration, its diaphragm being much, much lower in mass than the
cone affects the cone in so small a way as to be insignificant, and thus you
have a sound source riding on some other motion, so there will be Doppler
shift of the HF tone.
In the case of a speaker cone producing a complex soundwave, the LH
tone(s) and HF tone(s) not only affect each other, but are coupled tightly
together with no discernable coupling loss, thus producing, not a HF tone
riding on an LF tone (as is the case of the train and whistle), but a single
complex motion that results in the generation of a single complex soundwave
containing both (or all) frequencies, and thus not subject to Doppler
distortion in any normal sense.
In other words, if the LF is coupled to the HF, but the HF is not coupled
back to the LF, there will be Doppler shift in some form, but if both LF and
HF are solidly coupled in both directions the soundwave generaated is a
single coherent complex wave that isn't subject to Doppler shift in any
normal sense. The difference between the two is may seem small, but I think
it is critically important when considering Doppler distortion. Not being a
mathematician or physicist, I don't have the math background to produce the
necessary equations, but the mechanics are relatively simple so I can
visualize both models and see the differences, and I can assure you that
there are important differences in the two models.
If those with the above two assumptions will look at what makes them
think both assumptions apply to the speaker reproducing multiple
frequencies, and thoroughly analyze the two models I presented, I think
things may become a bit clearer for everyone.
I'm not postulating about pistons in closed or open chambers, I'm trying
to model real speakers in the real world.
Porky
> Bob Cain <arc...@arcanemethods.com> writes:
> > [...]
> > Does it sound like it yet? I've ordered a book that is said to prove
> > one of the axioms and Art Ludwig has consented to engage in the kind
> > of proof I think this deserves and to enter into discussion with me
> > about its specifics. That he wishes to continue our discussion
> > several weeks after it began should indicate that at least he sees a
> p> real desire in me to find and understand the truth as he obviously
> > does himself. However his in depth analysis turns out I admire him
> > greatly (and am very grateful) for his willingness to perform it in
> > public.
>
> I agree - I appreciate what Art is doing as well.
>
> > OTOH, if all your criticism means is that I haven't agreed with you
>
> Not at all, Bob. In fact, I get a charge out of seeing a false belief of
> my own get overturned. Makes me realize the universe is even more wondrous
> than I thought.
>
> > then perhaps a look in the mirror is appropriate.
>
> As Aerosmith said in a song once, "All those lines in my face getting
clearer..."
"Isn't that the way everybody's got their dues in life to pay...."
We're paying our Doppler dues right now. :-) I've spent 'way too many
hours on this, but I can't quit 'til I know how it turns out. The bad part
is that I may provide some clues here and there, right or wrong, but unless
I want to go back to school for several more years, I won't be providing the
mathematical proof, and I very well may not be able to understand the
equations that show the proof. I'll just have to hope that folks are honest
enough to admit the truth when they see it and tell me what it all means....
*L*
Mark
Ghost,
I think we agree on most points, but I disagree with you on this
particualr spcial case.
I belive Doppler exists whenever the distance between Rx and Tx is
changing.
But if the two cones are vibrating in phase (with zero phase shift) at
50 Hz, but not with zero time delay becasue they are seperated by a
fixed idstance, ( I do understand the distinction betwen zero time
delay and zero phast shift) then I belive in this special case, no
Doppler occurs because the distance form Tx to Rx is a constant even
though both are moving relative to the medium.
As an analogy, if there are two trains on the same track both moving
at 60 MPH in the same direction, does Doppler occur when one hears the
whistle of the other train. I don't think so.
Mark
Bob Cain
Randy Yates wrote:
> Not at all, Bob. In fact, I get a charge out of seeing a false belief of
> my own get overturned. Makes me realize the universe is even more wondrous
> than I thought.
Believe it or not, I will get the same charge if my belief
on this can be overturned by solid theoretical proof. No
way do I think I know everything and if there proves to be a
gap in my understanding, I very much welcome it being filled.
Of course it is nothing like the charge I'm going to feel
when I'm ultimately proved correct. :-)
The Ghost
> I think we agree on most points, but I disagree with you on this
> particualr spcial case.
> I belive Doppler exists whenever the distance between Rx and Tx is
> changing.
>
> But if the two cones are vibrating in phase (with zero phase shift) at
> 50 Hz, but not with zero time delay becasue they are seperated by a
> fixed idstance, ( I do understand the distinction betwen zero time
> delay and zero phast shift) then I belive in this special case, no
> Doppler occurs because the distance form Tx to Rx is a constant even
> though both are moving relative to the medium.
>
> As an analogy, if there are two trains on the same track both moving
> at 60 MPH in the same direction, does Doppler occur when one hears the
> whistle of the other train. I don't think so.
>
> Mark
Zero time delay means just that.....zero time delay and zero phase
shift. On the other hand zero phase shift occurs for finite time
delays each time the distance of the propagating wave increases by one
wavelength. For example, consider a loudspeaker radiating 1KHz in a
free field. If at some particular distance from the loudspeaker, the
phase shift is zero degrees relative to the electrical signal. The
phase shift will also be zero degrees for increased distances from the
loudspeaker of 1, 2, 3,..... wavelengths. So, even though you move
farther and farther away from the loudspeaker and increase the time
delay between transmitter and receiver, you can still find points in
space where the phase difference relative to the electrical signal is
zero degrees.
The Ghost
You are right, Bob. I am going to re-post it. I want to make sure
that everyone reading these newsgroups from now until the end of time
is fully aware of the sort of human being that Bob Cain really is.
The Ghost
> Valid and meaningful experiment always trumps theory. A
> _valid_ experiment is one with acceptable measurement of
> signal and in which no extraneous signal is admited or else
> any extraneous signal can be exactly accounted for. The
> experimenter is responsible for the proof of this. Peer
> review is usually required for acceptance of the proof.
BULL CRAP. The experimenter is only responsible for reporting
honestly the measurement methodology that he used and the results that
he obtained. If other experimenters do not believe the results, it is
up to them to repeat the experiment, identify the purported error,
correct it and obtain and present the corrected result. Also, you
mindless jackass, peer review is only required for acceptance for
publication. It is quite common for opposing articles on
controvercial topics to be accepted for publication even though the
issue in dispute remains unresolved.
> A _meaningful_ experiment is one that has been repeated with
> the same results by an independant experimenter with
> credentials and credibility among peers.
No. A meaningful experiment is one that yields the correct result.
And someone like yourself who is technically inept is not in a
postition to make that assessment.
> If testing a theory, which is the usual use of experiment in
> science, the parameter space of the theory must also be
> sampled at more than one point, if it is possible to control
> the parameters, and the results remain in agreement with
> theory at all of them.
Just another one of your mindless, irrational assertions/diversions.
A valid demonstranted inconsistency between theory and experimental
result is all that is required to disprove a theory. However, a
valid, demonstrated agreement at one point in n-dimensional paramater
space does not require that a theory be rejected. It simply means is
that the theory is still viable and that it can not be dismissed
simply because jackasses like you refuse to accept it until/unless the
theory has been proven to be to be in agreement with all possible
variation in parameters.
> I look forward very much to such an experimental test of
> whatever predictive theory emerges from this discussion. I
> would wish it were in the hands of one not so invested in a
> particular result but that's what the requirement of
> repeatability by a disinterested party is for.
More BULL CRAP. The theory is there, but you refuse to accept it.
Also, you are in serious need of a reality check. The way science
works is one group of scientists trying to to prove that their theory
is correct, or that the theory of another group of scientists is
incorrect. You are a naive and totally midnless idiot if you believe
that science progresses on a disinteressted-party basis.
Jim Carr
news:b5fb78ba.04082...@posting.google.com...
> No. A meaningful experiment is one that yields the correct result.
Knowing the correct results in advance sounds like good science to me!
Bob Cain
Jim Carr wrote:
What would even be better for that particular experimenter
is to make sure he doesn't know the answer first. OTOH, if
the results match well a theory that can be falsified then
all that need be known about the experimenter has been said.
Randy Yates
This is pun, right?
An experiment's results are, by definition, correct.
You can't drop a ball from a roof and say, "That's incorrect - the ball
fell to the ground. It shouldn't have done that - it should have floated
to the sky. I must have the experiment wrong." It may perhaps be the case
that the experiment you perform tells you little or nothing about the
question(s) you are seeking to answer, but the experiment's outcome is
nevertheless never "incorrect."
--
% Randy Yates % "And all that I can do
%% Fuquay-Varina, NC % is say I'm sorry,
%%% 919-577-9882 % that's the way it goes..."
%%%% <ya...@ieee.org> % Getting To The Point', *Balance of Power*, ELO
http://home.earthlink.net/~yatescr
Jim Carr
> "Jim Carr" <j...@azwebpages.com> writes:
>
> > "The Ghost" <the_gho...@netzero.com> wrote in message
> > news:b5fb78ba.04082...@posting.google.com...
> >
> >> No. A meaningful experiment is one that yields the correct result.
> >
> > Knowing the correct results in advance sounds like good science to me!
>
> This is pun, right?
Actually, I was shooting for sarcasm.
Mark
Yes I agree, and it is at these particular points of 0 phase shift
that you just described that the Tx cone and Rx cone are moving in
phase at 50Hz and therefore the distance between them is constant so
there is no Doppler effect.
Mark
Angelo Campanella
> Yes I agree, and it is at these particular points of 0 phase shift
etc.
PLEASE DO NOT CROSS POST INTO THIS ACOUSTICS GROUP, NOR CROSS POST FROM
THIS ACOUSTICS GROUP INTO OTHERS. LET'S KEEP FOCUSED ONLY ON ACOUSTICS.
ANGELO CAMPANELLA
Bob Cain
Angelo Campanella wrote:
I DON'T UNDERSTAND WHY YOU DON'T CONSIDER THIS A MATTER OF
ACOUSTIC THEORY.
Bob Cain
Mark wrote:
> Yes I agree, and it is at these particular points of 0 phase shift
> that you just described that the Tx cone and Rx cone are moving in
> phase at 50Hz and therefore the distance between them is constant so
> there is no Doppler effect.
Bingo. It can hardly be put more succinctly.
Bob Cain
Randy, in case you use it as a bit bucket and wouldn't know
this, I've sent you a brief email at the address you use for
these posts.
Randy Yates
> Mark wrote:
>
>
>> Yes I agree, and it is at these particular points of 0 phase shift
>> that you just described that the Tx cone and Rx cone are moving in
>> phase at 50Hz and therefore the distance between them is constant so
>> there is no Doppler effect.
>
> Bingo. It can hardly be put more succinctly.
Bob,
Is this the essence of what you've been trying to say all along? I.e.,
that, when the frequency is low enough, no energy is coupled into
the wave, so that the low frequency movement occurs in the transmitter
but not the receiver, but then when the frequency is high enough for
energy to transfer, the receiver cone moves with the transmitter?
I kinda sorta see what you're saying, but something sounds funny
about this. Can't put my finger on it right now.
--
% Randy Yates % "Remember the good old 1980's, when
%% Fuquay-Varina, NC % things were so uncomplicated?"
Bob Cain
Randy Yates wrote:
> Bob Cain <arc...@arcanemethods.com> writes:
>
>
>>Mark wrote:
>>
>>
>>
>>>Yes I agree, and it is at these particular points of 0 phase shift
>>>that you just described that the Tx cone and Rx cone are moving in
>>>phase at 50Hz and therefore the distance between them is constant so
>>>there is no Doppler effect.
>>
>>Bingo. It can hardly be put more succinctly.
>
>
> Bob,
>
> Is this the essence of what you've been trying to say all along? I.e.,
> that, when the frequency is low enough, no energy is coupled into
> the wave, so that the low frequency movement occurs in the transmitter
> but not the receiver, but then when the frequency is high enough for
> energy to transfer, the receiver cone moves with the transmitter?
No, but rather that for a Piston In A Tube you could
substitute any frequency for 50 Hz and Mark's statement
would be true. For the PIAT case, as you know, I think I've
found what will be a very simple proof that no Doppler
mixing will occur and that the Rx gets exactly what the Tx
sends based on one axiom that is at Art's site and Fourier
theory. You can't get down to many fewer first principles
than that. For anyone who wants to anticipate that proof,
the axiom is equation (1) at:
http://www.silcom.com/~aludwig/Physics/Piston_collisions.htm
I doubt anyone could find a hole if I were to just verbally
state it but I want to do better than that and it shouldn't
be very difficult except for one as rusty at proof as I am.
What you said is very close for systems other than the PIAT,
such as a speaker swinging on a rope or a speaker on a train
or ultimately for the speaker in a stationary cabinet. It
is the frequency dependant decoupling of motion of the Tx to
the Rx that causes Doppler mixing.
>
> I kinda sorta see what you're saying, but something sounds funny
> about this. Can't put my finger on it right now.
I know you will be trying. :-) Thanks very much, at the
very least, for giving it consideration. Getting just that
much for these ideas has proven incredibly difficult.
Bob Cain
Bob Cain wrote:
> No, but rather that for a Piston In A Tube you could substitute any
That should have said, "Yes, and that for a Piston In A
Tube...".
And when I said you are "very close", I should have said you
are "spot on".
Sorry,
Porky
Quite true, but the time delay will increase by the duration of the
particular wave cycle with each wavelength distance from the signal. In the
case of a 1 KHz sine wave, this would be an increase of one millisecond in
time delay between the electrical wave and the acoustic wave for roughly
every foot of distance between the source and the listener. I'm not sure I
see any particular relevance in the phase relationship between the
electrical and acoustical waves except in the case of sound reinforcement
where feedback or source/reinforcement interference might be a problem.
The Ghost
Who said anything about knowing the correct result in advance, you
fucking moron. Read some science history, asshole!
Jim Carr
LOL! Do you kiss your mother with a mouth like that?
Bob Cain
Jim Carr wrote:
>>Who said anything about knowing the correct result in advance, you
>>fucking moron. Read some science history, asshole!
>
>
> LOL! Do you kiss your mother with a mouth like that?
His mother isn't allowed in his room and he's afraid to
leave it because of talking shit to so many people and
reaching out to touch them in such kind ways as calling the
CEO of the company that they work for over personal matters
or clipping bits of usenets posts without context to email
to someone in order to poison a conversation in progress.
He really does have good reason to be paranoid and he keeps
multiplying them. A real class act but he knows no
acoustics or physics so he can be pretty safely ignored.
The Ghost
> "The Ghost" <the_gho...@netzero.com> wrote in message
> news:b5fb78ba.04090...@posting.google.com...
> > "Jim Carr" <j...@azwebpages.com> wrote in message
> news:<ndwYc.62149$yh.14812@fed1read05>...
> > > "The Ghost" <the_gho...@netzero.com> wrote in message
> > > news:b5fb78ba.04082...@posting.google.com...
> > >
> > > > No. A meaningful experiment is one that yields the correct result.
> > >
> > > Knowing the correct results in advance sounds like good science to me!
> >
> > Who said anything about knowing the correct result in advance, you
> > fucking moron. Read some science history, asshole!
>
> LOL! Do you kiss your mother with a mouth like that?
No, but I wouldn't be surprised if I have unknowingly kissed both your
wife and your daughter.
Jim Carr
> No, but I wouldn't be surprised if I have unknowingly kissed both your
> wife and your daughter.
What's with the belated replies? Did your therapist tell you to stay away
from the newsgroups for a week or something?
You're a sad little man. Your "science" is funny and your insults are not.
How pathetic.
Porky
One thing is for certain, Gary, you had better hope you never run into
any of us face to face. Frankly, I would be very surprised if you had ever
kissed any female other than your mother.
The Ghost
I don't have a therapist and I don't get up each morning eagerly
awaiting to find out the latest insult that you have bestowed upon me.
You are the one, not I, who is sad, little and pathetic. You have
not had anything technically substantive to contribute, and it is
clear that you are now simply on a hate crusade. I suggest that you
go into a corner and play with yourself because I am not going to
waste any more of my time playing that game with you.
The Ghost
> One thing is for certain, Gary, you had better hope you never run into
> any of us face to face.
Not my hope, but certainly my preference. It would be best, but not
for the reason/outcome that you imply.
>Frankly, I would be very surprised if you had ever
> kissed any female other than your mother.
And I would be very surprised if you have ever kissed anyone of the
opposite sex.
Porky
> "Porky" <no...@nospam.com> wrote in message
news:<gb57d.6438$yp....@bignews1.bellsouth.net>...
>
> > One thing is for certain, Gary, you had better hope you never run into
> > any of us face to face.
>
> Not my hope, but certainly my preference. It would be best, but not
> for the reason/outcome that you imply.
I implied nothing, and you're welcome to take my remark any way you choose.
> >Frankly, I would be very surprised if you had ever
> > kissed any female other than your mother.
>
> And I would be very surprised if you have ever kissed anyone of the
> opposite sex.
And I would be surprised if you even knew which was the opposite sex....
*LOL* Gary, you can't possibly win this one, so perhaps you should go back
to the physics groups, where everybody knows your name, and where you're a
legend in your own mind.
The Ghost
> "The Ghost" <the_gho...@netzero.com> wrote in message
> news:b5fb78ba.04100...@posting.google.com...
> > "Porky" <no...@nospam.com> wrote in message
> news:<gb57d.6438$yp....@bignews1.bellsouth.net>...
> >
> > > One thing is for certain, Gary, you had better hope you never run into
> > > any of us face to face.
> >
> > Not my hope, but certainly my preference. It would be best, but not
> > for the reason/outcome that you imply.
>
> I implied nothing, and you're welcome to take my remark any way you choose.
>
> > >Frankly, I would be very surprised if you had ever
> > > kissed any female other than your mother.
> >
> > And I would be very surprised if you have ever kissed anyone of the
> > opposite sex.
>
> And I would be surprised if you even knew which was the opposite sex....
>
> *LOL* Gary, you can't possibly win this one,
LOL again. Then, recognize that in a mud-slinging match everyone
winds up completely covered with the same mud. The only distinction
among participants is that such a condition is quite normal to swine
like you.
> so perhaps you should go back
> to the physics groups, where everybody knows your name, and where you're a
> legend in your own mind.
Perhaps, you should stay here where your gross technical ignorance
will continue to be tolerated, where nobody really cares who or what
you are, and where the fantasy that you have anything technically
substantive to say exists solely in your own mind.
The Ghost
news:G%o7d.88648$as2....@bignews3.bellsouth.net:
>
> "The Ghost" <the_gho...@netzero.com> wrote in message
> news:b5fb78ba.04100...@posting.google.com...
>> "Porky" <no...@nospam.com> wrote in message
> news:<gb57d.6438$yp....@bignews1.bellsouth.net>...
>>
>> > One thing is for certain, Gary, you had better hope you never run
>> > into any of us face to face.
>>
>> Not my hope, but certainly my preference. It would be best, but not
>> for the reason/outcome that you imply.
>
> I implied nothing, and you're welcome to take my remark any way you
> choose.
The tone, meaning and implication of your statement is obvious to anyone
who has half a brain. It is clearly an implicit threat and your denial
won't change that. Nonetheless, if, as you claim, your statement implies
nothing, please clarify for everyone reading this exchange now, as well as
anyone who is may read it in the future, precisely why I had better hope
that I never run into any of you face to face. Also, who specifically is
"us"? Should I expect to see your mother running down the street toward me
swinging a frying pan? While I would have no problem sending you to the
sausage factory, I would hate to be put in the uncomfortable and unpleasant
position that required me to shoot your mother in the foot. Finally,
perhaps you should disscuss your implicit threat with your audio-group
friend Bob Cain because he recently made a very similar threat in one of
his more vulgar recently-posted diatribes.
Porky
Yep, us pigs and southern rednecks just love that mud, and you'd know
why if you had ever seen a good ol' female mud rasslin' contest, that is if
you happen to be interested in females...
BTW, the amount of mud one accululates on one's person in a mud-slinging
match is inversely proportional to the imagination and creativity one uses
in slinging the mud. You got a lot more on you than I did.
> > so perhaps you should go back
> > to the physics groups, where everybody knows your name, and where you're
a
> > legend in your own mind.
>
> Perhaps, you should stay here where your gross technical ignorance
> will continue to be tolerated, where nobody really cares who or what
> you are, and where the fantasy that you have anything technically
> substantive to say exists solely in your own mind.
Finally, a bit of creativity in your reply, perhaps I misjudged you a bit
(but just a bit). You managed to phrase an insult without using any of those
tired old gutter slang expressions of which you seem to be so fond. In any
event, you started this particular mud-slinging contest because you thought
we were defending Bob Cain. It had nothing to do with anything technical, or
even whether you thought we were right or wrong.
Porky
"The Ghost" <theg...@sbcglobal.net> wrote in message
news:Xns9576BC3627122t...@64.164.98.29...
> "Porky" <no...@nospam.com> wrote in
> news:G%o7d.88648$as2....@bignews3.bellsouth.net:
>
> >
> > "The Ghost" <the_gho...@netzero.com> wrote in message
> > news:b5fb78ba.04100...@posting.google.com...
> >> "Porky" <no...@nospam.com> wrote in message
> > news:<gb57d.6438$yp....@bignews1.bellsouth.net>...
> >>
> >> > One thing is for certain, Gary, you had better hope you never run
> >> > into any of us face to face.
> >>
> >> Not my hope, but certainly my preference. It would be best, but not
> >> for the reason/outcome that you imply.
> >
> > I implied nothing, and you're welcome to take my remark any way you
> > choose.
>
>
> The tone, meaning and implication of your statement is obvious to anyone
> who has half a brain.
You, in other words...
>It is clearly an implicit threat and your denial won't change that.
It is neither an implicit nor an explicit threat, and I not only implied
nothing, I denied nothing, I said you may take it anyway you choose.
>Nonetheless, if, as you claim, your statement implies
> nothing, please clarify for everyone reading this exchange now, as well as
> anyone who is may read it in the future, precisely why I had better hope
> that I never run into any of you face to face.
Since anyone with a whole brain would understand the meaning of what I
said, I don't think it needs clarification. In light of the unearned insults
you've cast my way, I'd prefer to leave you in the dark. BTW, do you know
how to keep a moron in suspense?... I'll tell you later.
To make it simple enough for even you to understand, you don't like us
and we don't like you, so it would be an unpleasant experience for all
concerned if we were to meet you face to face, and be forced to spend any
time with you. You've shown here that you're a rather unpleasant person to
be around, and you've also shown that you're a rank amateur at the high art
of trading insults, so it would be more unpleasant for you than for us. The
"us" would be all those you've chosen to insult for no valid reason.
>Also, who specifically is
> "us"? Should I expect to see your mother running down the street toward
me
> swinging a frying pan?
My mother is dead, you jerk, and if she were alive, she wouldn't need a
frying pan to deal with you. She would just look pityingly at you and walk
on.
>While I would have no problem sending you to the
> sausage factory, I would hate to be put in the uncomfortable and
unpleasant
> position that required me to shoot your mother in the foot.
Now who is making threats? You are making direct public threats against
me and against my mother. Nothing implied there! You have threatened to kill
me and to shoot my mother, and I'm sure the authorities (and the attorney I
work for) will be quite interested to hear about this. Of course you're
mentally, physically, and emotionally incapable of carrying them out, so I'm
not worried, but you have violated news group policy, and the law as well.
Your apparent lack of intelligence is matched by your apparent lack of
common sense!
Also, you must be one hell of a coward to have to threaten to shoot an old
woman in the foot, even in implied self-defense.
> Finally,
> perhaps you should disscuss your implicit threat with your audio-group
> friend Bob Cain because he recently made a very similar threat in one of
> his more vulgar recently-posted diatribes.
As I said, I made no threat, implicit or otherwise, so if Bob made a
similar statement, I would assume that he made no threat either. Perhaps you
should seek treatment for your paranoia.
The Ghost
> It is neither an implicit nor an explicit threat, and I not only implied
> nothing, I denied nothing, I said you may take it anyway you choose.
snip.....snip
> Since anyone with a whole brain would understand the meaning of what I
> said, I don't think it needs clarification. In light of the unearned insults
> you've cast my way, I'd prefer to leave you in the dark. BTW, do you know
> how to keep a moron in suspense?... I'll tell you later.
> To make it simple enough for even you to understand, you don't like us
> and we don't like you, so it would be an unpleasant experience for all
> concerned if we were to meet you face to face, and be forced to spend any
> time with you. You've shown here that you're a rather unpleasant person to
> be around, and you've also shown that you're a rank amateur at the high art
> of trading insults, so it would be more unpleasant for you than for us. The
> "us" would be all those you've chosen to insult for no valid reason.
For "no valid reason?" You are either brain dead or you are in
serious need of a reality check. For starters, I suggest that you
re-read your insulting diatribe (above). Then go back and re-read
your posts for the last few weeks and tell me why they should be
considered anything other than a litany of personal insults.
> My mother is dead, you jerk, and if she were alive, she wouldn't need a
> frying pan to deal with you. She would just look pityingly at you and walk
> on.
Assuming that your mother was a honorable person, you obvously didn't
take after her. In light of your pathetic and disgraceful behavior,
it is more likely that she would look pityingly at you and walk on.
> Now who is making threats? You are making direct public threats against
> me and against my mother. Nothing implied there! You have threatened to kill
> me and to shoot my mother, and I'm sure the authorities (and the attorney I
> work for) will be quite interested to hear about this. Of course you're
> mentally, physically, and emotionally incapable of carrying them out, so I'm
> not worried, but you have violated news group policy, and the law as well.
> Your apparent lack of intelligence is matched by your apparent lack of
> common sense!
> Also, you must be one hell of a coward to have to threaten to shoot an old
> woman in the foot, even in implied self-defense.
The extent of your stupidity is clearly not limited to audio matters.
You really need to re-read my post. I made no threats to kill anyone,
and your assertion that I did is absurd and preposterous.
> As I said, I made no threat, implicit or otherwise, so if Bob made a
> similar statement, I would assume that he made no threat either. Perhaps you
> should seek treatment for your paranoia.
If I were paranoid, treatment is available. Unfortunately no
treatment is available that would enable you to overcome your gross
technical incompetence.
Porky
I suggest that YOU go back and look, because you started insulting me merely
because you thought I was defending Bob Cain, I said nothing out of the way
to you until you started inslutlng and cursing me. I've only posted insults
in response to your litany of insults, and mine were much more imaginative
and creative than yours were. It is you who need the reality check, and I
would suggest you get it from a professional before it is too late, if it
isn't already. Your behavior here has been hostile at best, and has bordered
on the edge of paranoid psychosis.
>
> > My mother is dead, you jerk, and if she were alive, she wouldn't need
a
> > frying pan to deal with you. She would just look pityingly at you and
walk
> > on.
>
> Assuming that your mother was a honorable person, you obvously didn't
> take after her. In light of your pathetic and disgraceful behavior,
> it is more likely that she would look pityingly at you and walk on.
Now I know you're psychotic and it seems that you may very well have a
deathwish as well.
> > Now who is making threats? You are making direct public threats
against
> > me and against my mother. Nothing implied there! You have threatened to
kill
> > me and to shoot my mother, and I'm sure the authorities (and the
attorney I
> > work for) will be quite interested to hear about this. Of course you're
> > mentally, physically, and emotionally incapable of carrying them out, so
I'm
> > not worried, but you have violated news group policy, and the law as
well.
> > Your apparent lack of intelligence is matched by your apparent lack of
> > common sense!
> > Also, you must be one hell of a coward to have to threaten to shoot an
old
> > woman in the foot, even in implied self-defense.
>
>
> The extent of your stupidity is clearly not limited to audio matters.
> You really need to re-read my post. I made no threats to kill anyone,
> and your assertion that I did is absurd and preposterous.
>
I know what you said, and so does everyone else here. My attorney friend
informs me that no court in the land would be likely to interpret my
previous statements as a threat against you, implied or otherwise. On the
other hand, considering that I go by the name "Porky" here, your statement,
"While I would have no problem sending you to the sausage factory,... etc",
could be legally construed as a death threat against me, and if I took you
seriously, I would be within my legal rights using any means of self defense
necessary if you approached me.
> > As I said, I made no threat, implicit or otherwise, so if Bob made a
> > similar statement, I would assume that he made no threat either. Perhaps
you
> > should seek treatment for your paranoia.
>
> If I were paranoid, treatment is available. Unfortunately no
> treatment is available that would enable you to overcome your gross
> technical incompetence.
It would seem that you are suffering from paranoid phychosis with
delusions of technical competence, and are halucinating that you actually
know something.
If I were really technically incompetant, education is avaliable that
would cure it. There is no cure for your paranoid psychosis, you will
require medication for the rest of your life.
The Ghost
> I suggest that YOU go back and look, because you started insulting me merely
> because you thought I was defending Bob Cain,
I started insulting you because you are one of the most
technically-inept jackasses posting in the audio newsgroups.
Initially, I judged you solely on the basis of the technical
accuracy/content your posts.
> Your behavior here has been hostile at best, and has bordered
> on the edge of paranoid psychosis.
snip....snip
> Now I know you're psychotic and it seems that you may very well have a
> deathwish as well.
snip.....snip
> My attorney friend
> informs me that no court in the land would be likely to interpret my
> previous statements as a threat against you, implied or otherwise. On the
> other hand, considering that I go by the name "Porky" here, your statement,
> "While I would have no problem sending you to the sausage factory,... etc",
> could be legally construed as a death threat against me, and if I took you
> seriously, I would be within my legal rights using any means of self defense
> necessary if you approached me.
Your attorney friend is a whore, and the advice he is giving you is
not worth any more than what you are paying him. The clear and
undeniable context of my statement pertained to the possibility of you
approaching me, not me approaching you. You need not worry about me
approaching you because I avoid stepping in shit at all cost.
> It would seem that you are suffering from paranoid phychosis with
> delusions of technical competence, and are halucinating that you actually
> know something.
> If I were really technically incompetant, education is avaliable that
> would cure it. There is no cure for your paranoid psychosis, you will
> require medication for the rest of your life.
Please pass me another air sickness bag. You are clearly no more
competent/qualified in the area of psychoanalysis than you are in
scientific/engineering/technical matters.
On the usenet, morons with a Beavis & Butthead mentality can call
Einstein a fool. Now, I am not implying that I am an Einstein, but I
do think that a reality check is long overdue. Accordingly, what
specifically are your academic credentials that enable you to justify
the assertions that you have made in the area of psychoanalysis and
science/engineering?
Jim Carr
> Your attorney friend is a whore, and the advice he is giving you is
> not worth any more than what you are paying him. The clear and
> undeniable context of my statement pertained to the possibility of you
> approaching me, not me approaching you. You need not worry about me
> approaching you because I avoid stepping in shit at all cost.
I have to give credit where credit is due. Your insults are definitely
improving. We're so proud of you!! Everyone has missed you so much since you
ran away in tears a while back. It's good to see you're back in form!
> On the usenet, morons with a Beavis & Butthead mentality can call
> Einstein a fool. Now, I am not implying that I am an Einstein, but I
> do think that a reality check is long overdue. Accordingly, what
> specifically are your academic credentials that enable you to justify
> the assertions that you have made in the area of psychoanalysis and
> science/engineering?
Here you go with the credentials thing again. The last ditch cry of the
defeated!
Bob Cain
The Ghost wrote:
> Now, I am not implying that I am an Einstein, but I
> do think that a reality check is long overdue.
Have at it. We all agree with you on both counts and we'll
give you all the time you need if you'll just shut up while
you're working it all out again.
> Accordingly, what
> specifically are your academic credentials that enable you to justify
> the assertions that you have made in the area of psychoanalysis...
"It doesn't take a weatherman to know which way the wind blows."
Porky
> "Porky" <no...@nospam.com> wrote in message news:<Kyq8d.139780
>
>
> > I suggest that YOU go back and look, because you started insulting me
merely
> > because you thought I was defending Bob Cain,
>
> I started insulting you because you are one of the most
> technically-inept jackasses posting in the audio newsgroups.
> Initially, I judged you solely on the basis of the technical
> accuracy/content your posts.
More of your ectoplasmic bullshit...
You should, because if you were to step in shit, it would be impossible to
ascertain which is the shit and which is you.
> > It would seem that you are suffering from paranoid phychosis with
> > delusions of technical competence, and are halucinating that you
actually
> > know something.
> > If I were really technically incompetant, education is avaliable that
> > would cure it. There is no cure for your paranoid psychosis, you will
> > require medication for the rest of your life.
>
> Please pass me another air sickness bag. You are clearly no more
> competent/qualified in the area of psychoanalysis than you are in
> scientific/engineering/technical matters.
I never claimed to be an expert in either.
> On the usenet, morons with a Beavis & Butthead mentality can call
> Einstein a fool. Now, I am not implying that I am an Einstein,
I certainly hope not, you are much, much closer to Beavis and Butthead
than you are to Einstein.
>but I do think that a reality check is long overdue. Accordingly, what
> specifically are your academic credentials that enable you to justify
> the assertions that you have made in the area of psychoanalysis and
> science/engineering?
Since I made no claim of expertise, I have no need to post credentials.
However, since you intimated a comparison of yourself to Einstein, perhaps
you should post your credentials...
The Ghost
> More of your ectoplasmic bullshit...
snip...snip
> .... if you were to step in shit, it would be impossible to
> ascertain which is the shit and which is you.
snip....snip
> I never claimed to be an expert in either.
snip.....snip
> ....... you are much, much closer to Beavis and Butthead
> than you are to Einstein.
> Since I made no claim of expertise, I have no need to post credentials.
> However, since you intimated a comparison of yourself to Einstein, perhaps
> you should post your credentials...
While you will no doubt deny it, the fact of the matter is that your
claim of expertise was/is implicit in your judgement/dismissal of my
opinions on the subject matter. While you are certainly entitled to
your opinions on technical matters, you are not justified in
dismissing mine without being willing to state your academic
credentials which may assign some credibility of your opinion.
Othewise, your opinion on the matter is just your opinion and has no
credibility whatsoever.
The Ghost
news:ck7q3...@enews4.newsguy.com:
>
>
> The Ghost wrote:
>
>> Now, I am not implying that I am an Einstein, but I
>> do think that a reality check is long overdue.
>
> Have at it. We all agree with you on both counts and we'll
> give you all the time you need if you'll just shut up while
> you're working it all out again.
With all due respect, you fucking, arrogant asshole, the question was not
directed at you. Furthermore, you are the one who is flaunting his
ignorance, and nees to shut up.
>> Accordingly, what
>> specifically are your academic credentials that enable you to justify
>> the assertions that you have made in the area of psychoanalysis...
>
> "It doesn't take a weatherman to know which way the wind blows."
> Bob
Apparently for you it does.
Porky
You have posted nothing even worthy of dismissal, just a piece on a
sound source mounted on a motor, which is not a model of a loudspeaker
producing two tones simultaneously, and thus not relevant to the discussion
about the existance of Doppler distortion in a speaker. That conclusion
requires only a modicum of common sense, so posting of qualifications isn't
necessary.
I don't like you, for obvious reasons, but if you post something that is
relevant to the discussion, I'll look at it without bias and if it's worthy
of consideration, I'll consider it. Who knows, I might even agree with you,
but if so it will be on the merits of your presentation and not because of
your academic credentials. Personally, there are no academic "credentials"
that you can post that will change my opinion of you, I believe in results,
not "qualifications".
Since I have promised to decrease the volume of my posts, I will no longer
be responding to your insults. If you post any on-topic technical info, I'll
comment if I feel that I can contribute something, but I no longer have the
time or the desire to trade insults with you.
The Ghost
> You have posted nothing even worthy of dismissal, just a piece on a
> sound source mounted on a motor, which is not a model of a loudspeaker
> producing two tones simultaneously, and thus not relevant to the discussion
> about the existance of Doppler distortion in a speaker. That conclusion
> requires only a modicum of common sense, so posting of qualifications isn't
> necessary.
You can assert whatever you wish, but unless you are prepared to back
up your assertions with appropriate cridentials, your assertions have
no credibility and represent nothing more than ignorant opinion.
> I don't like you, for obvious reasons, but if you post something that is
> relevant to the discussion, I'll look at it without bias and if it's worthy
> of consideration, I'll consider it. Who knows, I might even agree with you,
> but if so it will be on the merits of your presentation and not because of
> your academic credentials. Personally, there are no academic "credentials"
> that you can post that will change my opinion of you, I believe in results,
> not "qualifications".
You are not qualified to determine what is/not relevant to the
discussion, and you believe in nothing other than your
technically-inept opinion.
Jim Carr
> You can assert whatever you wish, but unless you are prepared to back
> up your assertions with appropriate cridentials, your assertions have
> no credibility and represent nothing more than ignorant opinion.
For the last time it's CREDENTIALS, not CRIDENTIALS. C'mon! I mean, you can
spell credibility right, but you can't manage credentials even after being
repeatedly corrected? You're so stipud.
The Ghost
> For the last time it's CREDENTIALS, not CRIDENTIALS. C'mon! I mean, you can
> spell credibility right, but you can't manage credentials even after being
> repeatedly corrected? You're so stipud.
Like a spelling error and your opinion really matter. Fuck off, asswipe.
Porky
> "Porky" <no...@nospam.com> wrote in message
news:<YbGad.86965$DV3....@bignews5.bellsouth.net>...
>
> > You have posted nothing even worthy of dismissal, just a piece on a
> > sound source mounted on a motor, which is not a model of a loudspeaker
> > producing two tones simultaneously, and thus not relevant to the
discussion
> > about the existance of Doppler distortion in a speaker. That conclusion
> > requires only a modicum of common sense, so posting of qualifications
isn't
> > necessary.
>
> You can assert whatever you wish, but unless you are prepared to back
> up your assertions with appropriate cridentials, your assertions have
> no credibility and represent nothing more than ignorant opinion.
>
Since you have posted no credentials either, that would apply to you even
more than it would to me, since you're the one claiming expertise.
> > I don't like you, for obvious reasons, but if you post something that is
> > relevant to the discussion, I'll look at it without bias and if it's
worthy
> > of consideration, I'll consider it. Who knows, I might even agree with
you,
> > but if so it will be on the merits of your presentation and not because
of
> > your academic credentials. Personally, there are no academic
"credentials"
> > that you can post that will change my opinion of you, I believe in
results,
> > not "qualifications".
>
> You are not qualified to determine what is/not relevant to the
> discussion, and you believe in nothing other than your
> technically-inept opinion.
That being as it may, I'm still better qualified than you are, because I
can spell "credentials"
Go back to sci.physics, Gary, you obviously know nothing about music,
recording, or home studios. Oh wait, I see... No Gary, it's spelled "h",
"o", "m", "e', the last letter isn't an "o".... *LOL*