15 16 17 19 300 7TH STREET, S.W. , REPORTERS BUILDING, WASHINGTON, D.C. 20024 (202) 554-2345 20 21 22 23 24 25 Docld: 322766636 g/ Mr. Barger. There will 79 be fewer echos from the shock- wave because the buildings behind won't be involved any more because the shockwave does not Mr. Sawyer. What I was contribute to the chee second grouping of these waves. Barger. The firing tend to diminish the number of shortening the total length of lengthening them. Mr. Sawyer. Can you Can you read what kind of a 'from those things? That is Mr. Barger. I have not yet mentioned. The go behind the rifle. wondering is if that could as opposed to the ole second more toward the underpass would echos from shockwaves thereby rather than impulses, I think, tell from those series of spikes? sound it is, or duplicate a sound very hard to do for a reason that radio has a limiter in it that is designed so that if you begin to shout at the microphone the radio still functions. In other words, it takes that extra loud sound and reduces it down to an acceptable level for transmission through the radio. So all sounds that are louder than some threshold of loudness will appear to have the same loudness. these spikes have approximately the same loudness. indicates that all of them are for compression in the radio. time they would have been very Page 31 You see all This louder than that threshold Therefore, to the ear at the loud relative to the motorcycle ALDERSON REPORTING COMPANY, INC.
7 2 3 eo , 9 5 a Psy & 7 a 3 8 N 3 A 9 Z = e 10 Z <= a 11 = g 12 @ : 33 jen) fae} z 14 a 2 15 je] faa : 16 n e 17 je] a fH 618 en} m © 19 g. 20 21 @ » 23 24 25 Docld: 322766636 ' 80 but as heard through the radio they have been reduced in level sO as to go through the radio and since the motorcycle was already about as loud as the radio could pass, these spikes ' relative to the motorcycle noise have about the same loudness through the radio whereas an observer would have heard them above the motorcycle. GY So recreation working backwards from these to what was heard is virtually impossible because of that distortion in the radio by the limiter. I am glad you asked that question because I have to explain why all of the spikes have about the same amplitude. Now I have analytically calculated the peak sound pressure levels that I would estimate at a microphone on Elm Street due to the shooting and due to the defracted sounds from the buildings of the shooting and at least ten or twelve of these impulses I estimate to have a sound pressure level in excess of 110 decibels. The maximum sound pressure level that the microphone AIA and radio combination will pass is about 95 eg_100 decibels so all of those sounds would be limited down to that maximum level and they would come out looking the same whereas a person. in the Plaza would hear only a few of them because they would be so much louder than the others because his ear does not limit sounds, he would only hear the. very loud ones and the echos that came in one second later would be disregarded by the ear because they were so low relative to the loud ones. Page 82 ALDERSON REPORTING COMPANY, INC.
3 5 a % 6 a R 7 q 2 8 S a 9 Z & & 10 Zz < a 11 4 g 12 @ = 23 ~ joe] z 14 & 9 15 ica} jon] s 16 wa e 17 fa faa] mh 6(«18 = & 5 19 3 20 21 @ » 23 24 25 Docld: 3277666586 Page 33 81 The radio does not disregard them, it gives them as much wait as the loud ones. OP ate. Sawyer. Doesn't the average pistol projectal travel faster than 1100 feet per second? . 2 | Mr. Barger. There are supersonic 4 ' Mr. Sawyer. I know the 357 and the 44 Mag but doesn't a regular .38 travel faster? Mr. Barger. I am not certain. I am fairly certain a. -45 caliber is subsonic. I don't know about a .38. Mr. Sawyer. I would be surprised if they were under 1100 feet per second, myself, but I don't know the answer. Mr. Barger. “Iocan't really answer that question right now. I'll look it up. - | . | Chairman Stokes. In the final analysis in order for you to say with some degree of assurance what this really does represent insofar as 3 or 4 shots, what would be required? What do you feel would be necessary? Mr. Barger. In addition to the analysis that I have done, I feel I need two things. The first is to play or ‘transmit the sounds of the rifle through the radio that. we have obtained which is similar to the radio that transmitted these data to see if these shapes are in fact the shapes that that radio distorts the sounds into. I suspect that they are from analytical calculations that I have made but I feel I would have to see it with the real radio, principally because the ALDERSON REPORTING COMPANY, INC.
ee) =~ of) a so 6 Ww a a 7 a Ss 8 N oO A 9 Zz g = 10 Z = 4 1 2 g 12 < @:* jaa} N a 14 = fa] 2 15 i lou] = 16 i¢ 9] E 17 ical faa] BR 618 é - 19 3 20 21 e 7 23 24 25 82 t t limiting process I was describing is difficult to determine mathematically. Gwe expect to do that test early next week. The second thing I feel that is necessary as a test of the hypothesis that these groups of spikes are gunfire echos is a recreation with firing from the depository window, sixth floor, to the places where the car was at the times that these spikes occur on the assumption that the last one was the head shot. I think for completeness it would also be prudent to test fire from the knoll to those same targets and I would record through a microphone a well, through many microphones | al at about every 20 foot intervals up Elm and down Houston. I think it is necessary to show that these patterns of impulses with the face reversals included were in fact caused in Dealy Plaza by rifle fire directed in those directions. I believe such a test will indicate whether these patterns are rifle fire or are static. Those two things I believe are necessary to state whether these patterns of spikes are rifle fire and, if so, how many shots are here. Chairman Stokes. I have one further question and then, Floyd, I will yield to you. Are there other persons in the field who have your stature, or close to your stature, that can in some way corroborate your finding? Mr. Barger. Yes, there are. ‘Let me just qualify this ALDERSON REPORTING COMPANY, INC. Docld: 3277666586 Page 64
10 a) of a B 6 a g 7 a Ss 8 N io) a) 9 Zz e 5 10 z jen) 3 11 = Z 12 8 @ =} nN = 14 ce I Se 15 ica} fo Z 16 wn 2 17 I oe 618 = Fa > 19 3 20 21 oe ” 23 24 25 83 by saying that if you mean in the field of forensic acoustics I will say there is no such field. -I am a scientist that works ata research laboratory that has specialized in the study of acoustical phenomenon and there are other such laboratories. I think the best one is Bell Telephone Laboratory in Murrayville, New Jowcoye There are certain staff members there at that laboratory that I feel are eminently qualified to understand the acoustical phenomenon that we are dealing with and also the communications problems we are dealing with. A lot of this difficulty is caused by the radio and that is partly why I mentioned Bell Telephone Lab because they deal in acoustics and communication. | Sp I have mentioned to Professor Blakey that I feel that Dr. James Flanagan at BTL, Bell Telephone Lab, is a very qualified, knowledgeable scientist and I could name others if requested. Chairman Stokes. You have answered. Mr. Barger. Mr. Chairman, it might be appropriate for the record to note that I have talked to Mr. James Flanagan who, incidentally, is the President of the Acoustical Society of America. I happen to be an #xecutive gounselor at the Acoustical Society so he outranks me. Mr. Blakey. And he has agreed to talk to us on Monday and will give us a preliminary judgment as to whether he and “one or two other people like him in addition to him or in lieu ALVERSON REPORTING COMPANY, INC. Docld: 3277666586 Page 65
ll en) pes nN e 6 Ss & 7 a S 8 N oe) a 9 Z a & 10 z jan) a 11 4 3 12 . 8 @:3 fon) NM a 14 oa fon S 15 fl few} 5 16 ne 91 K 17 162] foo] ih «O18 E (19 3 20 21 e » 23 24 25 84 of him would come in and take a look at this material and decide whether we have enough to know whether to go to Dallas or whether additional tests ought to be run before we go to Dallas. We ought to have that. Yue. Sawyer. Doctor, if vou perform the tests in Dallas that you have related, would you expect then to be able to Say witha reasonable degree of certainty that it is or it is not,or it is three or it is four? Mr. Barger. Yes. I would expect to be able to say with a good deal of certainty that it was or was not shots and that these patterns were or were not caused by gunfire, and likewise, whether this last extended pattern could possibly have been caused by only one or was in fact two white Chairman Stokes. Mr. Fithian. Mr. Fithian. Doctor, in reading your Kent State report you were able by reconstructing the scene to have the placement of the van to the dormitory and so on to pin down the source of the gunfire to within, as I recall, just a very few feet. Mr. Barger. Five. Mr. Fithian. I told somebody today six. Mr. Barger. I remember it as five, it may be six. Mr. Fithian. My question is then whether or not the other end of this equation will be equally precise; that is, will you-be able to place the motorcycle within ten feet? ALDERSON REPORTING COMPANY, INC. Docld: 32776663586 Page 656
12 11 12 13 16 17 18 300 7TH STREET, S.W. , REPORTERS BUILDING, WASHINGTON, D.C. 20024 (202) 554-2345 20 21 @ 22 23 24 25 85 G) we. Barger. No; I don't believe so. I think it would require a good portion of a block to do that. In the Kent State work we had photographs that showed where each rifleman was standing and I also knew exactly where the microphone was. It was on a windowsill ina certain dormitory room and so I fired test shots from each of the places where riflemen were standing and recorded them at exactly where the microphone was and this enabled me to determine which rifleman fired which shot with great precision. We don't have that kind of pictorial evidence here about where the microphone was and I am going to seek-its location by placing microphones about every 20 feet. Mr. Fithian. So you would hope with good luck to locate the motorcycle within 20 feet? Mr. Barger. With luck I would get one of those micro- phones right on the spot. Mr. Fithian. Or in any event within 20 feet? Mr. Barger. Yes. Mr. Fithian. Now in the event a well, we can have all kinds of hypothesis about firing from the grassy knoll but in that case we have neither the origin of the blast nor the location of the microphone. How many ambiguities get created by that? Mr. Barger. The lack of knowledge of the source is as detrimental as the lack of knowledge of the receiver, if not ALDERSON REPORTING COMPANY, INC. Docld: 32727666586 Page 6?
13 2 . 3 “A z 6 = g 7 = N S 8 N 2) a 9 Z © & 10 Z 11 4 @ 23: ~ jaa 2 14 = 2 15 fq joa} : 16 if 9} e 17 <3} io] 5 618 x= & 5 19 ina] 20 21 @ 2 23 24 25 Docld: 322766636 86 worse. ‘The patterns that we will obtain in the recreation will not be identical to these unless we have both the source and the receiver in the same place... You will notice that the average distance between these impulses is about a tenth of a second. There are about te impulses in a second. The distance © traveled by sound in a tenth of a second is 110 feet. Since many of these paths are out to a building and back, that means an error in the distance to that building of half that or 55 feet. I think we can tolerate, therefore, errors in 55 feet. Sf ue. Fithian. One last question. The Elattening of the spikes, or the shortening of the spikes to be more accurate, resulted in a radial limited. Will this when combined with the uncertainty of the direction of any bullets fired from the grassy knoll make that data very sketchy? Let me just give you one background sentence. I presume that you would correlate the firing, at least point the rifle toward where the Kennedy car which is in a somewhat generalized direction. Mr. Barger. Yes. Mr. Fithian. The angle would vary depending where the shot was coming from. Mr. Barger. That is right. Mr. Fithian. I was not sure in your technical explanation from Congressman Sawyer's question about the possibility of that getting confused with an echo back from the structure of Page 88 ALDERSON REPORTING COMPANY, INC.
14 . re 5 5 nN 2 6 wd ae xR 7 a s 8 N io) a 9 Z e & 10 z x g 11 = g 12 @ 223: ~ joa! i a) & 14 & fac] 2 15 ic m 7 16 id a) E 7 je} oa 6 (O18 ee, Fal 5 19 Es 20 21 @ »x | 23 24 25 Docld: 322766636 87 the overpass. Will there be aistinctive characteristics, discernable characteristics between a shot fired from the observatory sixth floor angle even though that is at its flatest’ point and the kind of impulses you would get from something being fired from almost directly in the opposite direction? Uwe. Barger. Yes. The pattern of echos of the shockwave will differ markedly for bullets fired in those two different directions. As I said, I believe I can tolerate an error of about 55 feet in the location of where the bullet lands or where it was fired from. I won't be able to get an exact match if I have an error as much as 55 feet but I will get one to one correspondence of spikes. They won't occur at exactly the same place but there will be the same number of them and the pluses and the minuses will be in the same order and that is what I seek. ‘Now I think in the case of the shots from the depository we will get better correspondence if these shots are the echo of gunfire because we know almost exactly where the rifle is fired at to where it was fired. I can't expect such good correspondence from anywhere else, if indeed anywhere else shows any kind of correspondence at all. “Mr. Fithian. My last question, in your diagrams showing -the splitting of the sound, is it only the corner of the building that counts? Mr. Barger. No. That is a good question. The loudest Page 89 ALDERSON REPORTING COMPANY, INC.
15 10 a 12 13 14 15 16 17 300 7TH STREET, S.W. , REPORTERS BUILDING, WASHINGTON, D.C. 20024 (202) 554-2345 20 21 23 24 25 Docld: 322766636 88 sound will be the direct sound, it traveled from. the muzzle to the microphone. All. other things being equal, the next loudest sound would be a reflection. However, the position of that building facade is such that a reflection would not hit that microphone. The only building that would give you a reflection“is this one over here for this location for the microphone. The next loudest echos are corner defractions and I have drawn the cornered defractions here. SW wearer still are the surface scanners. This building has. a rough face, it has windows with windowsills and the like so that the sound that is incident upon that surface not only is reflected at the angle of incidence but very weakly scattered in all directions. Those weakly scattered signals are not going to be heard, they will be at least 20 decibels weaker. Mr. Fithian. Now in the event that you are picking up weaker defractions,: at what point, if at all, does the impact become low enough that they would not be limited by the receiver? Mr. Barger. My estimate is that sound traveling over the past that I have sketched here will all have a level at the microphone that is equal to or greater than the level at which the microphone begins to limit. The motorcycle noise, the other noise in the microphone is about ra decibels below that. The sound level or the level of sound scattered from the faces of these buildings would be at least 30 decibels lower than the Page 90 ALDERSON REPORTING COMPANY, INC.
16 10 1] 12 13 14 15 16 17 300 7TH STREET, S.W. , REPORTERS BUILDING, WASHINGTON, D.C. 20024 (202) 554-2345 20 21 @ 2 23 24 25 Docld: 32266636 89 corner defractions and, therefore, it would not be heard. Y ue. Fithian. Now all of your assumptions thus far have been that the motorcycle was somewhere roughly where you have it placed. Is there any other hypothesis that could be sketched out here since at least one motorcycle went off on the wreng street and one could be somewhere fx blocks away or tage blocks ‘away? Mr. Barger. Yes. Mr. Fithian. I am getting down to the same question if you were down there would the sounds and the impact and the echo still exceed the limit drawn here? Mr. Barger. Yes. There is a range distance from this point that includes the entire area up these streets half a block where some of the sounds would be that loud. The pattern of the echos of course would be grossly different but in order to do this properly we have to probe all of those places. So what we plan to do is each time we fire to have 12 microphones operating at once simultaneously. The first time we fire those 12 microphones will be located one on either side of the street every 20 feet of Elm Street here because this is where we feel the motorcycle is most Likely to have been and I am going to be analyzing these data as they appear. In other words, I will look at these patterns within en Minutes of the shots on oan oscilloscope and I am going to make overlays of these patterns to the same scale as the Page 91 ALDERSON REPORTING COMPANY, INC.
17 12 13 14 15 18 19 300 7TH STREET, S:W. , REPORTERS BUILDING, WASHINGTON, D.C. 20024 (202) 554-2345 20 2) © 22 23 24 25 ‘Docld: 322766666 11 90 oscilloscope; that is, hold them up one off the other. Y ye. Fithian. Do you still have your computer there that you run this thing on? Mr. Barger. Unfortunately, the computer that did this ‘is in a room this size. I will just be doing a squiggle analysis. If none of the patterns that we get on any of those 12 microphones are similar to any of these patterns that we have here, we will then pick the 12 microphones up and set them along here. .If none of the patterns that we get in the 12 micro- phones along this street match any of the patterns that we have in the filtered tape analysis, we will set them along here. If none match, then we will start putting them in more remote _ _| locations. If we are lucky, we will get it the first time. . If we don't get it within any radius of this area where we exceed the limit, I will conclude that these patterns are not gunfire or at least not gunfire in Dealy Plaza. I have suggested to Professor Blakey that we will be able to cover the places where motorcycles were known to be; in other words, along the route and up this street with four placements of the microphone arrays and so we would repeat the gunshcts four times at most, the pattern of gunshots. I indicated we would want to fire at four targets from here. Basically they correspond to where the car was at about l 1:58 A 97, 313 and this curve over here on the south side of Page 92 ALDERSON REPORTING COMPANY, INC.
18 2 3 eo , 8 5 a z 6 a x 7 a S 8 N ) f=} 9 z & ES 10 a 11 S g 12 @:3 5 2] wm & 14 E 2 15 ica} = 16 is 9] 17 <a) 2 h 618 co} & > 19 % 20 21 @ » 23 24 25 91 Main. That was apparently struck and so we would fire from this location at each of those four targets with the microphone — where, array in its fire position and then from chee each of those and then if we get no matches move the location and get the matches. YP Now if we could recover the known locations of motor-~ cycles with such maximum of 4, repeat. yer. Could I ask one question? Wyre Yr. Pre Chairman Stokes. Go ahead, Mr. Preyer. $usea +, Mr. Preyer. I understood you to say something about the pattern of pistol shots a little earlier to the effect that | they had a shorter pattern or fewer squiggles than a rifle shot. Mr. Barger. Yes. I was hypothesizing when I said that the pistol in question has a subsonic buttle in which case all of the impulses caused by the shockwaves would he absent. Now you pointed out that many pistols have supersonic bullets, and in that case my argument would not apply. Mr. Preyer. Did I understand you to also say that in the second part of the long three second pattern that some of the indications there wexe different from the first part of the patterns that were thrép seconds, that some had a shorter pattern? Mr. Barger. Yes. There are fewer impulses in the second pattern of this last long group than there are in the first pattern or in the pattern that is the second pattern pocta:32266686! Page 93 ALDERSON REPORTING COMPANY, INC.
19 WW 12 13 14 15 18 19 300 7TH STREET, S.W. , REPORTERS BUILDING, WASHINGTON, D.C. 20024 (202) 554-2345 20 21 @ 22 23 24 25 Docld: 322766636 92 than in the first. rhe second half of the large third pattern which may be a pattern which itself has the fewest number of impulses. ot A ase. Preyer. And that isj;the only one, in all of the patterns, that is a unique pattern in that respect? Mr. Barger. Yes. Let me refresh my memory. Mr. McKinney. If you would yield a minute Z Mr. Barger. I count off impulses in this fourth pattern. I count 16 impulses in the third, 16 in the second and 13 in the first. So there are the fewest in the last but not greatly so. Mr. Preyer. That is not a remarkable difference necessarily, in your art? Mr. Barger. That idfference I regard as plausible given the amount of motion of the microphone that I would expect between the shots, that is right. Mr. McKinney. Just on that I didn't know if they were repeatedly changed and Mr. Barger expanded on it. | Mr. Barger. I don't know the answer to that question. I suspect that since these sounds that are loud enough to be seen are severely limited by the radio transmitter anyway that even if that is true they would come out looking about the same. Mr. McKinney. I see. A&y ‘Chairman Stokes. How long aoRe the last patterns Page 94 ALDERSON REPORTING COMPANY, INC. °
93 20 1 fas? in terms of time? 2 G) wx. Barger. Let me tell you how long all four 3 patterns last also, if I may. ® 4 Chairman Stokes. I was going to ask that question 2 5 also. ae] a re 6 . Mr. Barger. The first pattern appears to be 82 hundredths a So . a 7 of a second. The duration of the second appears to be one x N 8 8 and offe hundredths of a second. The third one appears 5 a 9 to be 96 hundredths of a second and the fourth one 85 S : g 10 hundredths of a second. = a N Mr. Sawyer. I thought you said the last one, the = g 12 fourth, was three seconds. a © 5 13 Mr. Barger. Well, if one considers the last two a 1? 2 = 14 to be a single pattern, it lasts thee seconds. It looks e S 15 to me like it is more like two and I have been describing fo} Z 16 it as two. 5 7 | Mr. Fithian. With the second roughly. ion} & 18 | Mr. Barger. Yes. es 3 19. You will observe from the numbers that I have read 2 20 that the first and the last are more like each other and 21 the second and third are more like themselves in terms © 22 of impulses in the duration. I don't apply much significance 23 to this kind of detail in these patterns without an 24 opportunity to verify these patterns. 25 Chairman Stokes. Mrs. Burke. ALDERSON REPORTING COMPANY, INC. Docld: 3277666586 Page 935