In article <50gh4j$njj@lex.zippo.com>, Greg.Jaynes@zippo.com says... > >In
article <32296380.16D1@usa.net>, Anthony says... >> > > >I've noticed a
few comments about the acoustical evidence which I >suspect may be
misleading some people. I will try to address a few >points where I
believe the information posted has been incorrect. > > >* I have posted
some remarks where I believe your information is incorrect. > > > >Doppler
Effect. > >First, no one has ever proven that there are portions of the
tape which >exhibit what most people are calling a Doppler Effect.  > > >*
This is the kind of statement that misleads people. What proof do you
require? >* It is obvious that the siren sounds exhibit the Doppler
effect. >* >* First you say there is no proof of Doppler effect then your
following statements >* discuss the Doppler effect and what it may mean.
>
>

Just because someone says something is so does not prove the fact. Some
people have said that there is a Doppler Effect on the DPD tape.
Unfortunately, many people who know nothing about acoustics will pick up
that tidbit and say, "Ah ha, that proves that the motorcycle with the open
microphone was parked, not part of the motorcade." Not true. There can be
Doppler shifts whether the open microphone is moving or not.
I have no problem with discussing the importance and ramifications of various
theories, whether I believe in them or not. The fact that I discuss something
does not ergo mean that I believe in it.
I merely pointed out that no one has proven that there was a Doppler Effect
on the tape. I believe that there are several places on the tape where there
are Doppler shifts. Can they be reliably measured? Can they be quantified?
We we draw any useful conclusions from their characteristics?

>
>Second, the fact >that there is any Doppler Effect does not in and of
itself prove that >McLain's cycle had the open microphone or not. > > > >*
If McLains microphone was stuck on, the sound of the siren should be
constant >* recording the sound of his own siren. The fact that the sound
is not constant proves >* it was not his microphone.  > > Which siren?
There are several sirens heard on the tape. What do you mean by constant?
Increasing and decreasing decibels are not a Doppler shift. I assume that
you are talking about the siren on the cycle with the open microphone,
whether you grant that it is McLain's or feel that it someone else's. That
siren would show any Doppler shifts. Would the sound be constant? It
depends on what you mean by constant. The pitch of the siren on the open
microphone would naturally rise and fall. Is that a Doppler shift? How
could it be when the position of the siren stays the same relative to the
open microphone, give or take less than an inch due to the movement of the
frame of the cycle. What is the true pitch of the siren? What are the true
pitches of the other sirens? Are they the same as the siren on the cycle
with the open microphone? Unless the cyclist with the open micrphone is
stationary next to other parked cyclists with their sirens on, there will
be some slight difference in relative speed. Unless you get rid of more
unknown variables you can not tell if the cycle with the open microphone
is parked and other cycles are passing his location, or he is moving past
parked cycles with their sirens on, or he is riding his cycle and passing
and/or being passed by other cycles with their sirens on.  In order to
measure a Doppler shift, you have to assume that the pitch of the source
is constant. On a police siren it isn't. 
 
>
> If the open microphone
>was on a moving cycle and/or the sirens were on other vehicles which
>were moving relative to the open microphone, there would naturally be
>some type of Doppler Effect. If the open microphone was moving at about
>the same speed as the other vehicles with sirens wailing, then the
>Doppler Effect would be neglible, and perhaps not even measureable. If
>the vehicle with the open microphone is stationary while the other
>vehicles are moving,
>
> OR the other vehicles are moving at increasing or
>decreasing speeds different from the moving open microphone, there will
>be some Doppler Effect. 
>
>
>* The issue of course, is the siren sounds on *the* Dallas Police tapes. 
>* Not the hypothetical musings above. The stuck microphone recorded the 
>* of sirens coming toward it , passing and going away. The siren sound only
>* lasts 36 seconds. It would take much longer than that for McLain to drive
>* to parkland hospital. Not only should we hear sirens two minutes sooner
>* than we do, we should hear them for at least four minutes which would be 
>* the earliest possible time to get to Parkland from Dealey Plaza.
>*
>* That is of course *IF* McLain had the stuck microphone.
>
Why should we hear sirens two minutes sooner? It took McLain about two minutes 
to catch up with the front of the motorcade. Remember that he started near
the middle of the motorcade and did not leave Dealey Plaza immediately.
Several other motorcyles likewise did not leave Dealey Plaza immediately and
did not turn on their sirens. Why should McLain be an exception?

My musings were not hypothetical. I was listing the various probable
situations which must be considered when you are examining a Doppler shift.
How can you tell which is moving, the source, the hearer, or both?

>
>The fact that there is a Doppler Effect of some >type does not tell you
which vehicles are moving. It may be possible to >figure out exactly which
vehicles were moving, but we need to get rid of >more unknown variables to
do that. Has anyone done that? Will anyone >attempt to do that? In order
to do so, it would be extremely helpful to >have access to the original
tape. But the HSCA locked it up. The >National Archives is supposed to
make it available to the public, but >withdrew it when I requested it. The
FBI and DOJ have stalled my FOIA >attempts to get it for 15 years. So, in
short, such an analysis could be >done, but could easily be dismissed as
not having been done on the >original material. > >* Do you expect to hear
something different on these tapes? >* >* The National Archives should
release the tapes. We already have them anyway. >* It just makes it look
like they are hiding something. And it makes an issue that >* dedicated
researchers are never going to let go until they do. > I can do the
analysis on the tapes I have, but it is so simple for WC defenders to
simply dismiss any analysis by pointing out that it was not done on the
original tape. > > >Lastly, what some people have been calling a Doppler
>Effect is simply the cascading effect of the wailing police siren which
>naturally rises and falls. When you stand next to a parked cycle with
>its siren on, you hear the pitch go higher and lower. > > >* The Dallas
Police motorcycle sirens ran from a friction device connected to the >*
front wheel. If the motorcycle was not moving it could make no siren sound
at all. >* The "Cascading" of the siren can tell us generally the rate of
speed - constant - >* accelerating - decelerating. > The point about the
siren only sounding when the cycle is moving is interesting. I asume you
can prove some type of documentation of that fact? I had not considered
using that argument. If true, it might alone prove that the cycle with the
open microphone was moving, as it appears that one of the sirens we hear
was actually on the cycle with the open microphone. At about 263 seconds
after the microphone became stuck for the period including the shots,
there is an arcing sound of electrical intereference immediately before a
new siren is turned on. I believe that is when McLain turned on his cycle.
If you are correct about there being no sound if a siren is turned on
while a cycle is parked, this alone would prove that the cycle with the
open microphone was moving, not parked. Interesting. If the pitch of the
siren rises and falls with accleration and deceleration, then you can not
reliably measure the Doppler shift. In order to reliably measure the
Doppler shift, you need to assume that the source has a constant pitch. 

>
> A thorough >analysis of a Doppler shift assumes that the originating
pitch is at a >constant, unchanging frequency. (That also becomes a
problem when you >analyze the bell sound as the pitch of a struck bell
changes slightly >with time) > > > >*The definition of the Doppler effect
does not categorically eliminate a changing >* frequency. It does however,
as you indicate, explain the principle in terms of >*a constant frequency. 
So, as the frequency changes, you could still measure any >* portion of
the ocillation in terms of the Doppler effect. >* >* For example:  Forget
about a recorded siren sound. Use your own life experience. >*When you
hear an ambulance siren with your own ears coming toward you then
>*passing and going away. Do you not hear the Doppler effect? The siren on
the >*ambulance was not a constant frequency. >* >*It is the same thing we
hear on the channel one stuck microphone sequence. > Sure, based on life
experience, I can easily detect a Doppler shift, even from a siren which
does not maintain a constant pitch. That is one reason why I believe there
are Doppler shifts on the DPD tape. But has anyone proven it? Has anyone
quantified them? Do we have any firm data upon which to draw conclusions?
> > >The presence of Doppler shifts on the DPD tape does not pinpoint the
>location of the open microphone. > > >*I have no problem with the
statement above. (pinpoint being the keyword) > >One could just as easily
argue that it >was on a parked motorcycle at the Trade Mart which then
picked up the >sounds of nearby passing motorcycles. One could also argue
that it was >on some other cycle in the motorcade. > > >*Except for the
sirens. The sirens are the key. THEY SHOULD BE CONSTANT >* IF McLAINS
MICROPHONE WAS STUCK ON. > The sirens can not be constant, unless McLain
maintained exactly the same speed as every other vehicle with its siren
turned on, a practical impossibility. McLain started way behind the front
of the motorcade and had to speed up to catch up. The estimated speed of
the limo, SS car, and lead car was about 70 MPH on Stemmons. What should
be constant? The pitch or the volume? If you mean volume, you are not
talking about Doppler. If you mean pitch, you just stated that
acceleration and deceleration alone would fluctuate the pitch. Measure the
Doppler shift and let me know what speeds you come up with. Be slightly
suspicious if your answer exceeds 400 MPH! 

>
>The one element which pinpoints the location of the cycle is the pattern
>matching done by Weiss and Aschkenasy. They identified the paths of over
>20 echoes of a shot from the grassy knoll arriving at a moving open
>microphone on Elm Street at the time of the head shot or just before. > >
>* Of course Weiss and Aschkenasy were not measuring siren sounds or in
fact >* any sounds at all.  And I respectfully submit that they were not
performing >* pattern matching as you say. >* >* They were measuring ECHO
RETURN TIMES. >* >* It's one thing to produce a sound and then measure the
time of the returning echo. >* And quite another to select a point on a
spectrograph that represents sounds recorded >* by a microphone that was
being overwhelmed by engine noise. Then try to match them. 

Yes, the acoustical analysis was not as easy due to the engine noise.
A similar analysis had been done before in the Kent State case and the
defense stipulated to the accuracy of the results. Some of the basic
concepts have been used before and continue to be used to locate the
source of shots.

>*
>* However much confidence you place in the idea that the microphone
actually recorded >* impulse's of rifle shots firing super sonic bullets,
the siren sounds are undeniable. >* >* And the siren sounds would indicate
the McLain's microphone was not the one stuck . > > > >The only motorcycle
(or any other vehicle or person) which could have >been in that left lane
of Elm Street at that time was H.B. McLain. The >BBN study indicates that
McLain would need to be close to the corner of >Elm and Houston at the
time of the first shot. > > >* No. The BBN study does not indicate that
McLain would need to be close to the corner >* of Elm and Houston. It
indicates , that * if * they have correctly identified >* spectrographic
impulses as gunshots, then the microphone that recorded them >* would have
to be within nine feet of the point where their test microphone number >*
four was placed.  > Test microphone 2(4) was close to the corner of Elm
and Houston. It seems more logical, given matches to test microphone 2(5)
that the cycle would have been within 9 feet farther up Houston towards
Elm than the test microphone. The 9-foot radius was only one of the design
limits. It is not a magical number in and of itself. > > Could he? Yes. He
would have had to speed up to cover the distance up Houston faster >than
the rest of the motorcade had done for a few seconds. Did he? Yes. When
>McLain is seen in the Hughes film rounding the corner of Main onto
Houston, he was >behind camera car 3. When he is seen in the Dorman film,
he has passed camera 1 and is >starting to turn from Houston onto Elm. So
he has clearly been going faster than the rest >of the motorcade up
Houston. > How does the Dorman film synchronize with the Zapruder film?
That is >the crux of the matter. > > Until this summer I could only argue
that it was >possible that McLain got to the required position to pick up
the echoes >in time. A couple of months ago I got a copy of Robert
Groden's new >videotape, which includes the Dorman film. Preliminary
analysis seems to >indicate that McLain was at the right place at the
right time. I noticed >something which no one else seems to have noticed.
In the Dorman film, >we can see Rosemary Willis running past the top of
the reflecting pool. >This is the same little girl who is seen running in
the Zapruder film. >Unfortunately there is a break in the Dorman film
where she stopped to >rewind. Groden believes she took about 6 seconds to
rewind, but she took >only 3 or 4 seconds, the timing would place McLain
at the right spot to >record the echoes of the first shot with little
doubt.  > > >* McLain said he was stopped on Houston street. He said he
could see >* through the square ornamental holes in the white wall across
from the reflecting >* pool. He said he could see Jackie on the trunk.
This would have to be around >* the area of the last shot! How could he be
where you theorize during the first shot? >* >* Do you think McLain is
lying about this? > It is possible that McLain was simply mistaken on this
point. However, in this case I believe he is lying. I think that there are
several Dallas police who would lie about anything if they thought that it
would cut off speculation about a conspiracy. If Bowles thought that the
mere fact that the sun rises in the east might somehow prove a conspiracy
allegation true, Bowles would state as a fact that the sun rises in the
west. Do you believe anything that Roger Craig said? 

Again, researchers should not rely on witness testimony. Check the evidence
for yourself. You can see in the Dorman film that McLain has passed camera
car 1 and is rounding the corner onto Elm.

>
>
>Please respond to me at anthonymarsh@usa.net in case my current ISP
>pulls the plug on me.
>
>Anthony Marsh
>
>* Greg Jaynes
>
>
>

Tony