Because, as I said, you only cite the WC testimony, never books, never
interviews, never statements from that day, never affidavits.
Just because you realize that the WC does not mean you aren't a WC
defender. You just forgive them their lies because you truly think it
was for the good of the country.
>> Because you only know about
>> the cover-up version of events, not the original version.
>
> Wrong. I already read the article you quoted below some time ago, and
> you cannot prove otherwise. You aren't sitting here beside me seeing
> what I do and do not read. The fact that I did not *mention* having
> read it before now does not prove that I didn't.
>
I don't have to be sitting there beside you to see what you are doing.
And you frequent admit these things even it it takes years to come out.
>> Mary Woodward was ordered by her editor to rewrite her story because the
>> first version sounded too conspiratorial.
>
> Wrong. It is simply said that her account did not sit well with the
> managing editor and city officials. Nowhere does it say that her editor
> ordered her to rewrite the story. Obviously she didn't rewrite the
Does it? What is the IT you are citing?
You have no way to watch her speaking about it on the Journalists
Remember symposium. And you certainly wouldn't be able to read any book
which discusses it and quotes her.
> story, or else I would not have been able to quote her verbatim above
> from that same story *as* *printed* stating that she thought the shots
> came from behind her and a little to the right.
>
What same story? Oh, you mean the rewritten story. Not the original story.
>> Various conspiracy authors have written about what she actually said.
>> One of them actually used to post here, but I think you scared him away.
>
> Who would that be?
>
Again you prove how clueless you are. You can't even figure who that
author is that I am quoting. Maybe because you don't understand that
some people have used aliases here. So if I quote something that was
written by some guy using the alias Careulo you'd say you have no idea
who that is.
Canuck.
Gee, I wonder why he is called Canuck? Is that a slur? Or is it that
he's a Canadian.
>> anyone had said or what I had read or heardв[3] The most significant
>> statement in her report, which was quoted by UPI later that day, was her
>> recollection as to the direction from which one or more shots originated:
>>
>> ³ŠAfter acknowledging our cheers he [Kennedy] faced forward again
>> and suddenly there was a horrible, ear-shattering noise coming from
>> behind us and a little to our right.²[4]
>>
>> Although Miss Woodward didn¹t specifically state what was
>> ³behindŠand a little to our right², which many readers probably assumed
>> stated: ³ŠI don¹t know if you are interested in thisŠbut one of the
>> fellows who works here is gone. Can¹t find him anywhere. He¹s 23, about
>> five-foot nine and weighs about 150 pounds. I¹d have to check the
>> payroll records to be sure, but I think he¹s been here a couple of
>> months. His name is Lee Oswald.²[5] Although this is the only time
>> Oswald¹s name was mentioned in the article, clearly the implication
>> being made was that Oswald was the one and only assassin involved.
>> Almost two weeks after the assassination, FBI agents Henry Oliver
>> and David Barry interviewed Miss Woodward, presumably at her home
>> located at 4812 Alcott; she was identified in their report as ³Employee,
>> Women¹s News² at the DMN.[6] Brief mention is made of the three other
>> employees who were standing alongside Mary. In regard to the source of
>> the shots, the report emphasizes that ³her first reaction was that the
>> shots had been fired from above her head and possibly behind her.² Mary
>> indicated that initially she thought one or two shots ³might have come
>> from the overpass which was to her right.² However, she had now come to
>> the conclusion that due to the ³Šloud echo, she could not say where the
>> shots had come from, other than they had come from above her head.² She
>> explained to the agents that she had noticed ³Šfive or six persons
>> standing on top of the overpassв No reference is made in the report of
>> the possibility of one or more shots coming from the grassy knoll or
>> picket fence area, which is more consistent with Miss Woodward¹s initial
>> report. Undoubtedly, the FBI and her employer were both delighted at her
>> uncertain recollections as of December 6, 1963.
>> Like many eyewitnesses, Miss Woodward was not questioned by the
>> Warren Commission or its staff members, even though Mark Lane made a
>> point of emphasizing her November 23 report during his open testimony in
>> Washington D.C. on March 4, 1964, a meeting attended by Chief Justice
>> Warren, Congressman Gerald Ford and Senator John Cooper, among
>> others.[7] Presumably Arlen Specter decided, when he traveled to Dallas,
>> that Jean Hill was an easier witness to discredit than a newspaper reporter.
>> Despite her assertion that gunfire appeared to be coming from her
>> right, two Dallas reporters decided in 1980 that the whole matter was
>> simply a mistake on Miss Woodward¹s part. This conclusion is contained
>> in an article published on August 17, 1980, defending the WARREN
>> REPORT¹s conclusions. With no evidence that they actually spoke to Miss
>> Woodward or others, Doug Bedell and Hugh Anyesworth of the now-defunct
>> DALLAS TIMES-HERALD provided their own explanation:
>>
>> ³Šthe origins of the so-called Œgrassy knoll theory¹ of a second
>> gunman can be traced to the simple mistake of a DALLAS MORNING NEWS
>> reporter out for lunch with her cohorts to watch the motorcadeÅ When
I said SEE and I mean Watch. As in have the videotape, which I do and
you do not.
> "The only thing that I guess I got myself in a little bit of controversy
> about, I said that the shots appeared to have come from behind me and to
> my right. And I did say seemed to, I didn't say they did come from that
> direction, because first of all, I have very great difficulty discerning
> the direction of sounds anyway -- I'm the kind of person on the thruway
> when I hear a siren I panic cause I don't know where it's coming from.
> And secondly, I had spoken to my friends just prior to the event,
> suggesting that the grassy knoll would be the perfect spot for an
> assassin. So I said it was somewhat like self-fulfilling prophesies
> that when it happened I naturally, I expected it to have come from where
> I predicted it would come from. So in reality I do believe they did
> come from the School Book Depository Building, so I get a little bit
> upset when I get put in the other column."
>
> Nowhere in the entire audio did she say her editor ordered her to
> rewrite the story, Anthony. If I'm, uh, "wrong," name the exact minute
> and second where she says anything even remotely like that. You know
I didn't say that was the source.
> you can't, because she didn't. She only said that there was a bit of
> controversy over what she said in the article.
>
> And what do you mean that I like coverups? Lol, yet another of your
> absurd claims. You haven't shown a coverup here, you've shown exactly
> the opposite of what you falsely claimed.
>
A cover-up when they change a lead story because it sounds too
conspiratorial.
And by then they knew it must not be a conspiracy at all costs.
> Now, unlike your silly, false predictions about me, I will now make what
> is almost certainly going to be an accurate prediction about you. In
> all these years, Anthony, I can only recall you admitting you were
> mistaken *once*. That was a few weeks ago when you admitted your error
That's because you refuse to read my messages.
She did not say the fence. That is your interpretation. I never claimed
that you thought she meant the TSBD. Maybe some WC defenders have.
>>> As I do not see her naming any other direction whatsoever for the sound
>>> of any shot, she appears to have thought all of the shots, not just one
>>> of them, not just some of them, but all of them, came from the fence,
>>
>> Because you are cherry picking the evidence.
>
> Nonsense. Quote her verbatim saying that her initial impression was
> that they came from more than one direction. You know you can't,
I never said that. Stop your phony challenges.
And I didn't make that claim.
> article doesn't even MENTION ***ANYTHING*** about what direction she
> thought the gunfire came from. And there is NOTHING in that ENTIRE TEXT
> about her editor ordering her to rewrite the story. NOTHING.
>
I didn't say it was in that text.
You have never back up any of your statistical claims and never will.
You can not be pinned down on any fact. It's like trying to nail jello
to the wall.
Quote what? You do clueless that you can't find the HSCA study?
Volume VIII
Report No. 4034
Analysis of Earwitness Reports Relating to the Assassination of
President John F. Kennedy
D.M. Green
January 1979
Prepared for:
Select Committee on Assassinations
Bolt Beranek and Newman Inc.
50 Moulton Street
Cambridge, MA 02138
129
TABLE OF CONTENTS
page
LIST OF FIGURES AND TABLES iv
SECTION 1. INTRODUCTION....................................1
2. LOCALIZATION OF SOUND...........................2
3. STATISTICAL SURVEYS............................9
3.1 Origin of Shots..........................9
3.2 Number of Shots.........................11
4. REPORTS OF TRAINED OBSERVERS...................14
4.1 Test Conditions.........................16
4.2 Analysis of Observers' Localization
Responses...............................17
4.3 Loudness and Apparent Size of Acoustic
Image...................................18
5. CONCLUSIONS..................................20
APPENDIX A. TRANSCRIPTION OF OBSERVERS' NOTES.........A-l
iii
iii
130
LIST OF FIGURES AND TABLES
page
Figure 1. Muzzle blast and shock waveforms from
Mannlicher-Carcano....................................2
2. Loci of muzzle blast and shock waves at two
times after firing of supersonic bullet...............4
3. Observers localizing source of sound along
path of bullet........................................6
4. Observer location at Dealey Plaza....................15
Table I. Thompson's analysis of origin of shots..................9
II. House Committee analysis of origin of shots....10
III. Number of people reporting various origins as a
function of the number of shots reported.......12
IV. Accuracy of forced-choice responses as to
origin (TSBD or knoll).........................17
iv
131
1. INTRODUCTION
The analysis of witness reports comprised (1) an examination of
two compilations of testimony given by witnesses present in Dealey Plaza
on November 22, 1963, (2) an analysis of how the sounds of gunfire in
Dealey Plaza would be perceived by witnesses located at different areas
in the Plaza, and (3) the reports of trained listeners who were present
during the acoustical reconstruction on August 20, 1978. The two
compilations examined were those by J. Thompson, in his book, Six
Seconds in Dallas, and by members of the staff of the House Select
Committee on Assassinations.
All earwitness reports, whether of those present in Dealey Plaza in
1963 or of the experienced listeners in 1978, must be examined with an
understanding of the characteristic acoustical behavior of gunfire in a
reverberant space. Section 2 of this report explains how listeners can
misjudge the source and number of shots in such a space. Section 3
reports the analysis of the two compilations mentioned above; Sec. 4
details the observations of trained listeners stationed in the Plaza
during the acoustical reconstruction.
1
132
2. LOCALIZATION OF SOUND
The nature of gunfire is such that three basic errors in Judgment
relating to the source and the number of shots are possible:
* confusion of the shock wave and the muzzle blast
* front-back reversals
* misjudgment of interfering echoes.
The acoustic stimulus, or shot, has two primary components: the shock
wave and muzzle blast (illustrated in Fig. 1); and several echoes, or
reflections.
FIG. 1. MUZZLE BLAST AND SHOCK WAVEFORMS FROM MANNLICHER-CARCANO.
2
133
Because a rifle bullet travels at supersonic speed, it generates a
shock wave that spreads acoustically in the shape of a cone, with the
bullet as the tip of the cone. The muzzle blast, which propagates at
the speed of sound, spreads out spherically from the source. Both of
these sounds are very loud. The shock Wave has a peak sound pressure
level of about 135 dB re 2x10-5N/m2, and the muzzle blast, a peak of 157
dB re 2x10-5N/m(2), at l m. The time between arrivals of these two
sounds at a given listener location can vary considerably, depending on
the listener's position with respect to the location of the rifle and
the path of the bullet. Since the amplitude of the shock wave
diminishes as one over the distance from the source and the amplitude of
the muzzle blast diminishes as one over the square of the distance from
the source, the relative intensity of these two sounds also varies
considerably from one listener location to another.
At any reasonable distance, both the conical and spherical waves
are essentially plane waves with respect to a small object such as an
observer's head. Thus, to determine the apparent locus of the source,
we need only take a perpendicular to the appropriate wavefront as it
sweeps over the observer. Figure 2 shows the geometry of the two waves
at two different times. The shock wave, at time 1, has just reached
the observer; its apparent locus is along the path of the bullet on a
perpendicular to the shock wave. At this time, the wave from the muzzle
blast has not reached the observer. At time 2, when the blast wave has
reached the observer, the apparent source of the shot is on a
perpendicular to the plane of the spherical blast wave and, therefore,
at the muzzle of the rifle.
3
134
FIG. 2. LOCI OF MUZZLE BLAST AND SHOCK WAVES AT TWO TIMES AFTER
FIRING OF SUPERSONIC BULLET.
4
135
Dr. George Gariner confirmed this analysis at a test carried out with
20 to 30 observers at the Aberdeen Proving Ground. The observers were
seated in rows parallel to the path of the bullet. The blast wave was
muffled by firing the rifle through a small hole in an enclosed van.
The reports of the observers are portrayed graphically in Fig. 3.
About 75% of the observers pointed at the path of the bullet, while 25%
pointed away from this path - but still perpendicular to the surface of
the conical shock wave.
This latter judgment is called a front-back reversal. If the sound
of the shock wave were not so brief, an observer would have time to
execute a head motion and tell whether the source was exactly in front
of or behind him. However, the shock wave endures for only about 1
msec and the blast wave about 5 msec; some front-back reversals are
therefore expected. Even if the muzzle blast is not silenced, the
observer may be confused. The further the observer stands away from
the muzzle and the nearer the path of the bullet, the more likely that
localization of sound will be based on the shock wave and, hence,
incorrect.
Some muffling of the blast wave will occur if a rifle is fired from
within an open window. Thus, in the acoustical reconstruction, the
rifle was fired from two locations in the TSBD: (1) in the plane of
the open sixth-floor window and (2) with the muzzle tip withdrawn 2 ft
from the plane of the window.
The buildings around the Plaza caused strong reverberations, or
echoes, that followed the initial sound by from 0.5 to 1.5 sec. While
these reflections caused no confusion to our listeners, who were
prepared and expected ot hear them, they may well have
136
FIG. 3. OBSERVERS LOCALIZING SOURCE OF SOUND ALONG PATH OF
BULLET.
6
137
inflated the number of shots reported by the suprised witnesses during
the assassination. The source of these echoes can be predicted from
the general geometry of the Plaza. For example, one hears a very
strong reflection from the Post Office Annex that arrives about 1 sec
after the shot, regardless of whether the rifle is fired from the TSBD
or the knoll. Because of the long delay, a listener located on the
knoll would recognize this as an echo but might place the source
somewhere in back of him, anywhere from the TSBD to the railway overpass.
From near the TSBD, a listener would hear a strong echo from the
general vicinity of the railway overpass. However, since the initial
disturbance, the shock wave from the bullet, would be almost directly
overhead -- an anomalous locus, especially if the rifle had been fired
from well within the TSBD - this echo would cause some confusion. The
general area of the knoll, to the right of the bridge, would then be a
prime candidate as the locus of the source. Even though this echo
occurs 0.8 sec after the shock wave, it is the first sound that would
make sense to the listener. On the other hand, listeners located near
the railroad overpass would react to the very strong reflections from
along Houston St.
For listeners in the Plaza area, the location of the rifle muzzle
relative to the window opening is a critical determiner of the perceived
sound. The further inside the building the muzzle is located, the
greater the potential for the shock wave to dominate perception. If
the muzzle of the rifle had been withdrawn and, therefore, little or no
blast were present for one or more of the shots in 1963, the
localization judgments of people in the Plaza would have been based
primarily on the shock wave, creating much uncertainty and lack of
agreement.
7
138
During the reconstruction, echoes were heard from the new hotel,
but they arrived some seconds after the primary sound and long after the
earlier echoes from structures bordering the Plaza. The hotel echoes,
therefore, did not interfere with the subjective evaluations in any way.
8
139
3. STATISTICAL SURVEYS
3.1 Origin of Shots
According to Investigator J. Basteri, 692 people were present in
the Plaza during the assassination. Two surveys of interviews and
testimony given by some of these people have classified the witness
reports as to the origin of gunfire into four categories: the TSBD, the
Knoll, Other (not TSBD or Knoll), and Don't Know (origin uncertain).
J. Thompson's compilation in Six Seconds in Dallas of 190 witness
reports is summarized in Table I.
TABLE I. THOMPSON'S ANALYSIS OF ORIGIN OF SHOTS.
TSBD Knoll Other Don't Know Total
25 33 6 126 190
13.2% 17.3% 3.2% 66.3% 100%
This sample of 190 is 27.4% of the total available witnesses. It is
difficult to know what, if any, bias is present in the selection of
these witnesses. The sheer size of the sample makes it difficult to
believe that a sizable selection bias was present. It is also difficult
to predict the effect of a selection bias, if one were present. How
could one tell what the witness was likely to report prior to the
interview? People were scattered over a large area of the Plaza, but we
do not know if equal proportions were selected from each area. This
factor could influence the results, since analyses reveal that a person
located near the knoll was more likely to report the knoll as the origin
of the shots than any other location; similarly, a person located near
the TSBD was more likely to report the TSBD as the origin of the shots
than any other location.
9
140
The House Committee compilation is drawn from witness interviews by
the Dallas Police Department and the FBI and from sworn testimony in the
Warren Report. The total number of reports in this survey is 178.
With very few exceptions, all these people appeared in the 190 sampled
by Thompson. Similar sample-selection uncertainties apply here as well.
The House Committee analysis is summarized in Table II.
TABLE II. HOUSE COMMITTEE ANALYSIS OF ORGIN OF SHOTS.
TSBD KNOLL OTHER DON'T KNOW TOTAL
49 21 30 78 178
27.5% 11.8% 16.9% 43.8% 100%
Over half the sample had some opinion as to the origin of the
shot; the majority of these reported the origin as the TSBD.
Twenty-one witnesses reported the Knoll as the source, 30 reported some
Other location, and only 4 witnesses gave more than a single location
for the shots. The Four reporting a dual or multiple location are
counted as "Other" in Table II. Of the 49 witnesses pointing at TSBD,
13 were at the depository itself, 16 were in the motorcade, and the
remainder were scattered throughout the area, including at the
Sheriff's Office, the overpass, the knoll, and the triangular park.
A breakdown of these reporting the knoll as the origin of the shots
show that 2 of 21 were located on the knoll. Eight were on the curb
along Elm St. on the knoll side or on that side of the motorcade
traveling down Elm St. Four were near the TSBD. One was on the east
side of Houston. Five were in
10
141
the triangular area bordered by Elm, Houston, and Main, and one was on
the railroad overpass.
An analysis of the "Other" responses showed no obvious pattern.
Some witnesses at the TSBD point toward Houston St.; others point down
Elm. Similarly, those at the Sheriff's Office point in an arc ranging
from west of TSBD to the railroad overpass.
Comparing this statistical analysis with Thompson's, the most
striking discrepancy is the relatively low percentage of witnesses
reporting origins other than the knoll or the TSBD in Thompson's
compilation. Another important difference is in the relative number of
people pointing at the TSBD is the knoll. Although the categorization
of a given response is somewhat arbitrary, the major discrepancy in the
two compilations must be laid to a difference in classification of
responses making up the compilations. Zapruder is listed in the
Thompson survey as pointing to the knoll, while his sworn testimony
before the Warren Commission was as follows:*
Liebeler: But you didn't form any opinion at that time as
to what direction the shots did come from actually?
Zapruder: No.
Hence, House Committee staff placed his response in the "Don't Know"
category.
3.2 Number of Shots
The House Committee compilation also categorized witness responses
according to number of shots attributed to the four
---------------------------------------
*Warren Report, Vol. 7, P. 572.
ll
11
142
different categories of origin. This analysis is summarized in
Table III.
TABLE III. NUMBER OF PEOPLE REPORTING VARIOUS ORIGINS AS A
FUNCTION OF THE NUMBER OF SHOTS REPORTED
No. of Shots Reported
Reported
Origin Don't
of Shot 2 2 or 3 3 4 Know Total
TSBD 3 2 38 2 1 46
(4.5)* (1.9) (35.5) (1.6) (2.4)
Knoll 5 2 11 0 2 20
(2.0) (0.8) (15.4) (0.7) (1.1)
Other 2 1 22 3 1 29
(2.9) (1.2) (22) (1.0) (1.5)
Don't 7 2 61 1 5 76
Know (7.5) (3.1) (58.6) (2.7) (4.0)
Total 17 7 132 6 9 171(+)
*Expected number of judgments if origin and number of shots
were independent judgments.
+Seven other witnesses report 1, 4-5, 5, 6, or 8 shots.
Reports as to the number of shots range from 1 to 8. Of the 178
witnesses, however, the vast majority, 74.2% (132/178), reported 3
shots, and the mean number reported was 2.98.
Given the scatter in the reported sources of the gunfire, one
tenable hypothesis is that only people in certain locations might hear
the knoll shot. We therefore sought to investigate to what extent the
data matrix was interrelated, i.e., to what extent does one Judgment
influence the other? One test for
12
143
this interrelation is to assume the converse --namely, that the
Judgments are independent and to determine how well we can predict the
entire data matrix on the basis of this hypothesis. The expected number,
which is given in parenthesis beneath the number of people actually
reporting, is calculated by determining the probability of each report
From the margins and assuming that a particular cell, the intersection
of that row and column, can be calculated from the product of the
probabilities. For example, 20/171 = .117 report the shot coming from
the knoll and 132/171 = .772 reported B shots. Thus, the Joint
occurrence of both events, assuming they are independent, is (.772)
(.117) = .09, and the expected number of such reports is (.09) (171) =
15.4. The number of people reporting shots in this cell of the matrix
is 11, 4 or 5 fewer than expected. By and large, the predictions are
excellent, and there is no reason to suspect that the two responses are
other than independent.
13
144
4. REPORTS OF TRAINED OBSERVERS
On August 20, 1978, Dr. Dennis McFadden of the Psychology
Department of the University of Texas and Dr. Frederick Wightman of the
Department of Audlology at Northwestern University listened to the three
sequences of shots fired during the acoustical reconstruction and
recorded their impressions. Appendix A contains a transcription of
their notes. Their reports concerned the apparent origin of shots, any
apparent secondary sources or echoes, how loud the shots were, and any
other remarks they felt appropriate.
Initially, we were uncertain as to how easy it would be to
determine the correct location and what degree of consistency there
would be among the observers. Hence, for the first sequence, and during
most of the second, the observers were located about 1 m apart and in
such a way that I could see and compare their responses. The
approximate observer locations each sequence are indicated in Fig. 4.
During the first sequence, Dr. Wightman correctly localized all 17
shots, and Dr. McFadden missed only l. Their general qualitative
descriptions and descriptions of the reverberations were also highly
consistent. We were, therefore, more confident about the consistency of
the reports, and during the latter part of the second sequence, Dr.
McFadden moved from his original location at the curb at the top of Elm
directly in front of the TSBD, to across Elm on the southwest corner of
Elm and Houston. For the third sequence, Dr. Wightman and I observed
from the grassy triangle formed by Elm, Houston, and Main Sts., while
Dr. McFadden observed from the railroad tracks, above the northern curb
of Elm.
14
145
FIG. 4. OBSERVER LOCATIONS AT DEALEY PLAZA.
146
My own impressions and the reports of Dr. William Hartmann, the
investigator of the "Jiggle analysis," were very similar to those of
McFadden and Wightman, although my own (hearing )is impaired by about 50
dB in my left ear. The primary manifestation of this difficulty was my
failure to hear some echoes if they occurred to my left. Thus, it would
seem that our observers, because of their special training and
experience, are only slightly more acute concerning nuances of the
echoes and reverberations and, perhaps, in separating the shock wave and
the blast wave than are untrained people.
The emotional condition of our observers during the test and the
emotional condition of the people during the assassination were
undoubtedly quite different. The influence of such emotion on the
localization Judgment may be quite large, but there is no way to
quantify this factor.
4.1 Test Conditions
The shot sequence was unknown to both of the observers. Because
repeats of certain shots were requested during the sequence, I was also
uncertain --despite knowing the planned sequence.
We requested three motorcycles to be running during the test to
provide some background noise that would approximate the original
listening conditions in Dealey Plaza. Unfortunately, these newer
motorcycles were not very noisy, but the shots were so loud that any
reasonable level of background noise would have been low in comparison
with the shots themselves. Our listening conditions were, therefore,
essentially representative of those at the time of the assassination,
except for our being able to hear some very-low-level, long-delay echoes
that originally might have been inaudible.
16
147
Our observers did know that there were only two possible locations
for the marksman, whereas there was considerably more uncertainty on
this issue at the time of the assassination. Signal uncertainty of this
kind generally does not seriously degrade the accuracy of Judgments, but
it does depend on the number of potential alternatives. In this case,
as we shall see, the localization reports made by the trained listeners
were, for the most part, of general areas, rather than specific windows
of a building. The total number of potential locations was not,
therefore, large and, thus, was likely to be representative of
localization responses given at the time of the assassination.
4.2 Analysis of Observers' Localization Responses
The descriptive comments made by the observers are difficult to
compare with any degree of precision. However, there was clear
agreement in their reports with respect to the apparent loudness of the
sounds and echoes and the apparent size of the acoustic image. After
each test shot, we asked the two observers to guess whether the shot was
fired from the TSBD or the knoll, independent of what the apparent locus
might be.
Table IV is an analysis of this forced-choice data.
TABLE IV. ACCURACY OF FORCED-CHOICE RESPONSES AS TO ORIGIN (TSBD
OR KNOLL)
Sequence Dr. Wightman Dr. McFadden
------------------------------------------------------------------
1 12/12 100% 11/12 92%
2 11/15 73% 14/15 93%
3 19/25 76% 23/25 92%
Overall 47/57 82% 53/57 93%
------------------------------------------------------------------
Overall Agreement 82%
17
148
The average accuracy of the reports is nearly 90%, and the
consistency between the two observers is 82%. Also, the average
accuracy is nearly exactly the same whether the shot came from the
TSBD or the knoll. Thus, this analysis shows high accuracy in
localizing the source of the sound and reasonably good consistency.
4.3 Loudness and Apparent Size of Acoustic Image
All observers rated the rifle shots as very very loud, and they
were unable to understand how they could have been described as a
firecracker or backfire. Only the pistol, which was subsonic, produced
a moderate loudness.
Practically all the rifle shots, whether fired from the knoll or
the TSBD, appeared to be diffuse and to occupy a very large acoustic
space. For example, the sound did not seem to come from the sixth floor
window of the TSBD, but from the right upper side of the building. This
apparently large source location may be a result of acoustic scatter of
the muzzle blast -either because of the building in the case of the TSBD
or because of the trees in the case of the knoll. Only the pistol shot
appears to have a reasonably constrained acoustic image and, for that
reason, could be localized with some precision.
One might consider whether silencers would change the apparent
loudness of the size of the image. The Garinther-Moreland study*
reports the average attenuation produced by a number of silencers as
being about 18 dB for all weapon-silencer combinations. Sound from the
supersonic weapons tested were attenuated
----------------------------------------
*"Acoustical Considerations for a Silent Weapon System: A Feasibility
Study," 1966, p. 70.
18
149
by 18.6 dB and 37.5 dB, but even with this reduction, the peak
overpressure was still very large. Two rifle-silencer combinations
produced peak overpressures of 138 dB and 120 dB at 3.8 m, clearly loud
enough to be easy to locate and clearly audible above the motorcycle and
crowd noise.
19
150
5. CONCLUSIONS
It is difficult to draw any firm conclusions relating the reports
of witnesses in the Plaza to the possible locus of any assassin.
Confusion between the shock wave and muzzle blast front-back reversals,
confusion caused by echoes, and the startle of the witness could all be
used to impeach the testimony of any particular witness. There is no
way of knowing which, if any, of these factors was most significant with
respect to any single observation made on November 22, 1963. Thus, one
witness can be assigned no more credibility than any other. For
example, even if a shot was fired from the TSBD, the witnesses standing
on the knoll would likely report the source of the shot in the following
way. The witness would presumably localize on the basis Of the shock
wave. With the path of the bullet behind the President's car, the
witness would perceive the apparent locus of the shot as being on a line
from himself to the bullet's path -- i.e., in the street or open park
behind the path of the bullet. ,Since this location is impossible, a
front-back reversal is likely. This front-back reversal would place the
source 180(deg). behind the bullet path and, hence, on the knoll.
Despite this uncertainty, two general remarks seem worthwhile--one
based on the test, the other on the statistical analysis.
First, it is hard to believe a rifle was fired from the knoll.
Such a shot would be extremely loud, even if silenced, and it would be
hard to imagine anyone in the vicinity of the knoll missing such an
event. An unsilenced pistol firing subsonic bullets also seems unlikely
because this shot was the easiest to localize of all the shots fired.
It produced the least reverberation. As an acoustic image, it was much
sharper
20
151
and less diffuse than that of the rifle, sounding much like a
firecracker. It is, however, conceivable that had a pistol been fired
from the knoll at about the same time a rifle was fired from the TSBD
the pistol shot would have been less easily localized, or even
completely masked from some vantage points. As an isolated shot,
however, it is extremely easy to localize.
Finally, if one accepts the hypothesis that a marksman fired from
the knoll and that other shots were fired from some other location, then
it seems most unlikely that only 4 of 178 witnesses would report a
single location as the origin of the shots. Despite the various causes
of confusion in the locus of any single shot, a second shot from a
different location should be distinctive and different enough to cause
more than four witnesses to report multiple origins for the shots.
21
152
APPENDIX A. TRANSCRIPTION OF OBSERVERS' NOTES
The tabular information in this appendix was transcribed from notes
made during the acoustical reconstruction on
August 20, 1978 by two trained observers --Dennis McFadden and
Frederick Wightman. Included in this table, along with their
responses, are the number of the shot in each sequence of test firing,
the origin of the shot, and the target fired upon. For convenience in
determining the positions of rifle, target, and listener, the reader may
refer to Fig. 4 of this report.
Abbreviations used within the table are as follows:
* T always refers to the TSBD and K to the knoll.
* In the column headed origin, Tp means the rifle was fired in the
plane of the sixth floor window of the TSBD, T2 means the muzzle was
withdrawn 2 ft from the plane of the window, K indicates a rifle shot
from the knoll, and Kp represents a pistol shot from the knoll.
A-1
153
A.1 OBSERVER: DENNIS MCFADDEN
A-2
154
A.1 cont.
A-3
155
A.1 cont.
A-4
156
A.1 cont.
A-5
157
A.1 cont.
A-6
158
A.1 cont.
A-7
159
A.1 cont.
A-8
160
A.1 cont.
A-9
161
A.1 cont.
A-10
162
A.1 cont.
A-11
163
A.1 cont.
A-12
164
A.2 OBSERVER: FRED WIGHTMAN
A-13
165
A.2 cont.
A-14
166
A.2 cont.
A-15
167
A.2 cont.
A-16
168
A.2 cont.
A-17
169
A.2 cont.
A-18
170
A.2 cont.
A-19
171
ADDENDUM A: REPORT ON THE TEMPERATURE IN DALLAS, TEX.,
NOVEMBER 22, 1963
172
ADDENDUM A: cont.
173
ADDENDUM A: cont.
174
ADDENDUM A: cont.
175
ADDENDUM B: REPORT ON WIND CONDITIONS IN DALLAS, TEX.,
NOVEMBER 22, 1963
176
ADDENDUM B: cont.
177
ADDENDUM B: cont.
178
ADDENDUM B: cont.
179
ADDENDUM B: cont.
180
ADDENDUM B: cont.
181
ADDENDUM B: cont.
182
> making all sorts of false claims about what the original sources say.
> You produced above original sources which *don't* say that Woodward's
> editor ordered her to rewrite her story. You falsely claim that I am
> wrong when I say that less than 10% of the witnesses said shots came
> from multiple directions. I'll bet when I end up reading the complete
> document from the HSCA, it'll say something rather different from what
> you claim.
>
Not what I said.
Unlike you I back up all my claims with facts. When challenged I produce
the documents. I even sometimes scan in newspapers and books when I know
that certain people here have no way to find them on their own.