21 10 VW 12 13 15 16 17 300 7TH STREET, S.W. , REPORTERS BUILDING, WASHINGTON, D.C. 20024 (202) 554-2345 20 21 @ 2 23 24 25 94 Dh ycs. Burke. I don't have any questions. I am sorry I came in in the middle of this. Mr. Barger. You may be behind the middle. Mr. McKinney. Actually I have to say I have never felt more ignorant in my entire life. I never understood sound transmission to start. with. Chairman Stokes. Anything further, Hal? Mr. Sawyer. No. Chairman Stokes. Anyone have any further questions? Well, if there is nothing further, we certainly 4 Mr. Fithian. I guess I do have one question. Chairman Stokes. Mr. Fithian. Mr. Fithian. In your total perspective of looking at the data, did you ever think that there were more than four? Have you ever had any reason to? Mr. Barger. Well, if it is useful for me to tell you the genesis of what I say, I will. The first time that I realized there were groups of impulses on this tape at this general time s in other words at about 12:31 +r was when I had analyzed the tape through a rather primitive band pass filter and looked at the output not in this computer format but on an ultraviolet recording format which is nowhere as good as this. At that time I had the impression that there were three groups of spikes and that the second group and the third together might each have been doubles. ALDERSON REPORTING COMPANY, INC. Docld: 327766656 Page 96
22%. rol 5 5. nN. 2 6 iQ aq & 7 = Ss 8 N oO A 9 z & & 10 Z 5 a 3 g 12 5 @:* m.: Q a 14. [oa o 15 io ms 3 16 is 2) f 17 & [a= 6 («8 eo Ee. o (I9 a 20 21 e ” 23 24 25 Docld: 322766636 95 Of we. Fithian. I see. Mr. Barger. After having filtered the tapes through these two filters and obtained these two recordings of the ‘output of the filters, I don't have that impression any more. Mr. Fithian. Have you done all of the enhancement techniques that there are extant in your science? Mr. Barger. Well, the answer to that has to be no. The graduate schools of America eurn out Ph.D. theses on new ways of filtering noise every day. I have employed the two most powerful methods of filtering that I know of that apply to the filtering of transients out in favor of continuing performance and the most powerful is this adapted filter, it is a Withrow leased mean square adapted digital filter. Withrow is a professor at one of the California universities who is perhaps the leading scientist in adaptive filtering and basically knows your filters that go out and find out what noise is and strike it out. The other filter, the band pass filter, is the most appropriate band pass filter of all other band pass filters that I can think of based on the known frequency spectrum of motorcycle noise and the known frequency spectrum of gunfire shockwaves. I selected that and not the motorcycle. So I used the most powerful adaptive filter that I know and the most powerful band pass filter that I know. There are several other classes of filters that are known for ALDERSON REPORTING COMPANY, INC. Page 37 ~
2» COS ps4 ON e 6 w a & 7 = N S 8 N 6) as 9 Z S & 10 Z jon} Q 11 g 12 8 @:* fae] nm & 14 i fant Se 15 jc joa] : 16 wa KF 17 ica [=~] A 618 jem) & 5 19 oo} 20 21 e * 23 24 25 Docld: 3277666586 Page 96 96 filtering out impulsive noise. These are used in speech analysis and we will probably use one to try to hear the speech more clearly than we hear later on in this record in an attempt to get a correspondence between radio ghannels l and 2. That type of filter is not appropriate really for us to maintain an impulse. The reason for that is speech is impulsive so if you use a filter that retains speech you are retaining impulses and so all of the impulse noise in here is unaffected by that. G Mr. Fithian. I hate to prolong this. Chairman Stokes. Take your time, Mr. Fithian. Mr. Fithian. What is the historical chronology of developments in your field? Behind that question is what might have been available at the time of the Warren Commission or what is now being used that was not even dreamed of at the Warren Commission date? Mr. Barger. ‘The bypass filter that I used was available then. Mr. Fithian. It was available then? Mr. Barger. yes. I don't believe Withrow had developed this filter at that time. Mr. Fithian. This sort of thing that you are doing, has that been done before 20 years ago, 15 years ago? Did they do this at all? Mr. Barger. To my knowledge I am the only person tnat ALDERSON REPORTING COMPANY, INC.
24 10 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 Docld: 322766636 97 has used echo pattern analysis to identify the location of or the existence of gunfire. I have never read of anyone else doing it but then no one has read of me doing it either - ‘because I didn't publish those results. fin other words, that report you read was initially ‘submitted to a grand jury and only became available when that proceeding was terminated. dr. Fithian. All right. Chairman Stokes. Where did you get your training in this field? Can you tell us something about your educational background? Mr. Barger. Well, I have a Bachelor's degree in mechanical engineering at the University of Michigan, a Master's degree in mechanical engineering from the University of Connecticut, a Master of arts in applied physics from Harvard and Ph.D. in applied physics from Harvard and I specialized in acoustics at Harvard. The use of acoustics for forensic purposes, forensic acoustics, is not anything that is taught anywhere that I know of. These techniques that I..am applying to this reconstruction and that I applied at Kent State were simply applications of acoustical and engineering principles that I learned over time. My professional background is one of acoustical research in underwater acoustics, medical ultrasonics. In the former case I looked at submarines and ALDERSON REPORTING COMPANY, INC. Page 99
98 25 ; in the latter case I am looking for cancer. Also a good 2 deal of research in the propagation of sound in the environment ry 3 va the abatement of noise from trains, trucks, airplanes, 4 . buses and also the design of concert halls. I do research 5 . . < in how to make a concert hall sound more like a concert. hall. N + 6 . . . 8 V so this particular analysis that Professor Blakey has x asked me to do I regard as a research project in acoustics N that involves the same principles that all those other 3 qj 9 Zz projects that I described to you involve day by day but I E 10 > don't believe that forensic acoustics or applying acoustics Ss . yn di SS in this way is a field. It certainly is not taught explicitly. ‘SF 12 A Mr. Blakey. And one would hope that we never have . = = £2 ; @ = 33 | ee e another occasion to which it might be. 2 14 B Chairman Stokes. Right. It is extraordinarily ea fii. ; I interesting data, though. - 16 . . = Mr. McKinney. It is too bad we don't have a recording 5 of the shooting of Dr. King; it would solve a lot of the = nan 18 = questions one sometimes asked us whether it was the second e 19 3 floor window or a grassy knoll here. 20 . Cee Mr. Barger. Since my scientific research does not 21 | include forensic acoustics unless somebody knocks on ny 22 @ door, I had long thought that if a tape recording existed of 23 . . ; . Kennedy's assassination that it would be extremely simple to 24 . find out where the shots were fired from and how many there were, etc. At least I thought this since I did the Kent State Docld:32266686" Page 100 ALDERSON REPORTING COMPANY, INC.
26° 10 11 12 13 14 15. 16 17 18 19 300 7TH STREET, S.W. , REPORTERS BUILDING, WASHINGTON, D.C. 20024 (202) 554-2345 20 | 21 Y 22 23 24 25 DoclId: 322766686 99 one. So when our Mr. Sullivan told me that you had called I thought there must be such a recording; you know, this will be duck soup. When Mr. Hornbeck of the staff brought the tape and I listened to it and realized how much noise there was on it, I realized it was not going to be simple and it is not really simple. We have had to filter the tapes rather carefully and eliminate as much noise as possible. FD chairman Stokes. It has been very educational for me and I am sure all of us this afternoon. Mrs. Burke. Mrs. Burke. I just wondered in an area of H particularly they use it in aircraft in determining directions. Is that the only place #esuppos¢ that we have had that? Was that state of the art used at any time when you were in a conflict? Mr. Barger. Yes. The Army did a study of the sound of rifle fire at helicopters from forests in order to help the people in the helicopter determine where the rifle fire was coming from. As a matter of fact, my company did some of the research to develop the instrument that would do that. That was a very simple problem compared to this one because there were no buildings around, it was just a nice acoustically soft forest with a bullet coming up out of it so one had only to listen to the shockwave, one snockwave, and the muzzle blast, one muzzle blast, and by the timing, telling the time between the two, he could tell where the gun ALDERSON REPORTING COMPANY, INC. Page 101
27 14 15 16 18 19 300 7TH STREET, S.W. , REPORTERS BUILDING, WASHINGTON, D.C. 20024 (202) 554-2345 20 21 y 22 23 24 25 DoclId: 322766636 100 was. In that case the bullet was presumed to have been fired at the helicopter so it was very loud and there was not much of a- noise problem but to answer your question, yes, they have gone that far. Y/ drs. urke. I am sorry I came at the end. Is there (woo a place on here that designates impact or what is analyzed as impact? Mr. Barger. The sound of impact? Mrs. Burke. Yes. Mr. Barger. No. I have no good knowledge of the sound of impact. I am quite certain that it is much lower than the shockwave and the muzzle blast that we have been talking about but I don't know how much more. It is conceivable that one of these impulses is an impact but only bearly conceivable because the impact on a soft object z- in other words, not the curve 7 would be described as a thud and heard as a thud and the sounds we are talking about would be heard as a crack anda bang. In other words, it is conceivable that some of these very drawn out low frequency signals are sounds of impact but I am certainly not considering them in my analysis. Mrs. Burke. Just one other thing. At any place on here with the amount of noise that was on that recording, do you measure at a decibel level below what human hearing would record? P ALDERSON REPORTING COMPANY, INC. age 102 ;
28 3s COS 3 2 . NS! 6 To] Sg R 7 x = 8 N S 6 9 Zz © & 10 Z ion Q 1] S g 12 a @:* joa] 2 14 & faa] Oo 15 <2 fad 3 16 if 9) H 17 <a) <= 5 18 x mB F 19 a 20 21 @ 22 23 24 25 Docld: 32266686 Page 103 101 Sf ue. Barger. No. To the contrary, everything that we can identify through this radio would have been extremely “audible to the ear. Mrs. Burke. I see. Mr. McKinney. Radios are more sensitive than the ear. Mr. Barger. Much. Mr. McKinney. The only time this gets simple is when you give a description. Mr. Sawyer. Is it possiblegjust listening with your ear to this recording, that you can detect a shot sound at all? Mr. Barger. No. One does not: have that sensation. Since the limiter has taken the loud report and brought it down to just a bearly audible level and the weak echos are left at that level, it sounds sort of like diteditsdit-=dit-dit= dit:dit. The reason it sounds so inaudible is these impulses only last wp or .thrée miliseconds and the human ear can bearly hear anything that lasts cw or thge miliseconds unless it is as loud as a gunshot but the limiter has made these quiet so it is so distorted that you don't have the impression of hearing gunshot. Just to listen to this filtered tape you hear this tch-tch-tch and it does not sound like gunfire. The bell on the other hand which is not limited by the microphone because it is bearly audible, it sounds like a bell. ALDERSON REPORTING COMPANY, INC.
29 re 5 pe) a z 6 a & 7 = N s 8 N oe} a 9 Z, £ & 10 Z a 1 2 y 12 3 fea] Nn S 14 a fou 2 15 [| low] 3 16 i? 9] & 17 g fa mH 618 ea & - 19 S 20 21 eo ” 23 24 , 25 DoclId: 322766636 102 G) mx. Fithian. Are those the only two identifiable sounds that you pick up from that thing except the motorcycle running? Mr. Barger. A lot of these large squiggles which occur occasionally in the outputs of both fielders are identifiably caused by the depressing of a button on somebody else's transmitter. They go tic-tic like this to try to get the attention of the dispatcher. You can see those, they are different than the impulses we are talking about and you can audibly detect those as being button clicks. ‘You can also hear very faintly, as I said, the sound of speech near the end of this ¢fyerminute period when the button was down and we think that that may have been from another police radio. Also further down the record about a minute after these patterns you hear audibly a great number of Sirens in the background 7 weakly but you hear them. Mr. Fithian. But all other sounds a the sound of the crowd, the sound of the cars that might be near the motorcycle at are overpowered. Mr. Barger. That is correct. when the motorcycle changes speed; you can hear that. In other words, you hear a urr-urr-urr-urr-urr-urr-urr-urr, this hammering sound, and then as ‘the noise diminishes as I said it did there you hear pulp-pulp-pulp and if you measure the time between those pulps, which sounded to the ear very much like a motorcycle throttling ALDERSON REPORTING COMPANY, INC. Page 104
30 down, you can show that the firing rate of the motorcycle is going down to 150 milisecons which is the standard item. 3 Ol we - . Fithian. Do you have any sensation that the motor- cycle was always on the move from the beginning to the end of w% 5 2 the tape? S 6 | ‘S| Mr. Barger. The speed of the motorcycle engine changes N a 7 x from time to time. There is no way that I can tell whether it N S 8 nN was in gear or what gear it was in so I cannot really say o a 9 Z anything about the actual speed over the ground unless and i} = 10 . F ‘ 5 until we find matches of these patterns with successively z a 1 S$ displaced patterns in the recreation, but from the sound of GS 12 | EB the tape you can't. a rs You don't get the impression of motion with at least 2 14 e the exception of the sirens, they seem to be going past the 5 15 si motorcycle or the motorcycle is going past them, and it is 7 16 = probably that they are going past the motorcycle because 3 somebody would not be sitting there with a siren. ~ 3 & : 18 = Chairman Stokes. Doctor, a twofold question. Does fmt = 19 s the age of the tape have anything to do with the manner in 20 ; Nb . which you are now able to analyze it? I guess Ynaly29 is not 21 the proper word. 22 ; The other is, can you tell whether or not anyone has 23 . . . . ever attempted to do anything with the tape to filter it or 24 . anything? 25 ; ; . . . Mr. Barger. We have the Dictabelt which is the recording ALDERSON REPORTING COMPANY, INC. Docld: 322766656 Page 105
31 1 12 13 14 15 17 18 19 300 7TH STREET, S.W., REPORTERS BUILDING, WASHINGTON, D.C. 20024 (202) 554-2345 20 21 @ 22 23 24 25 Docld: 322766636 104 medium of the police dispatch radio and we are actually analyzing a tape recording made from that Dictabelt some time ago. The reason we are doing that is that the Dictabelt has been blamed many times. since this original tape recording was made and in the process it has become very scratchy, very noisy, and in fact the needle skips when you play it now but the magnetic tape recording that we have which was made of that Dictabelt a long time ago was done before the Dictabelt was severely distorted and there are no needle jumps or anything on it. It is quite a good recording. We have the capability of listening to the Dictabelt and the tape to see if they correspond one to the other. We have not done that. We can, in other words, verify that the original recorded medium, the Dictabelt, is faithfully and non-tampered with, recorded, but we have not done it. Of str. Fithian. Recorded at proper speeds? Mr. Barger. The speeds are quite wrong. The time delays that I gave you are not those that you get by listening to the tape but have been corrected for the incorrect speed. We determined the correct speed in two ways. The first way we did a frequency spectrum analysis like the bell. In fact the bell is a reasonable illustration of it. This large spike is caused by a 60 cycle hum introduced in the Dictabelt recorder and this spike is supposed to be twice that or 120 cycles. Those are the powerline frequencies ALDERSON REPORTING COMPANY, INC. Page 106 ,
32. 2 3 eo + 8 5 on a Ps 5 7 a 3 8 N 3 6 9 z S 5 10, Z a 11 = g 12 . 8 @:” fas] ND 5 14 & fan] So 15 je jaa] z 16 i? 2] E17 fa low] 5 618 x & 5 19 a 20 21 oe ”* 23 24 25 105 and are very accurate in any city because people run their electric clocks by them. ‘When we analyze these tapes, I have analyzed the frequency of this 60 cycle hum at every contiguous one second interval throughout this period and I have found that 60 cycles comes out as 57 in every case which means that the Dictabelt tape recording process is running 5 percent slow because that 57 should be 60. 1 order to verify that analysis we have listened to the entire tape, two hours of it, with a stopwatch and every time the dispatcher gave the annotated time of day we would note the elapsed time, true elapsed time. So then we get a graph on the abscissa, the time that the dispatcher claims it is on the ordinant, the time our stopwatch says it really is since the time the tape began. If the tape is running at the right speed, those times will go along the 45 degree line. It turns out that the tape is not running at the right speed so the dispatcher is getting more and more out of sync. We also calculated the average error that the dispatcher makes each time he annotates the time because he only gives whole minutes and he does not give the whole minute exactly when the second hand is at the top, he gives it whenever he feels like it. We have been able to show that the standard error of the dispatcher's annotations is 30 seconds... In other words, he is as likely to be 30 seconds off as not as is to be expected if somebody is looking at the minute hand and ALDERSON REPORTING COMPANY, INC. Docld: 322766636 Page 107
33 14 15 16 17 19 300 7TH STREET, S.W. , REPORTERS BUILDING, WASHINGTON, D.C. 20024 (202) 554-2345 20 21 rs 22 23 24 25 DoclId: 322766636 106 not at the second hand. So by those two methods, tracking his annotations and by calculating, analyzing the frequency of the powerline, we have determined and corrected for the incorrect tape. That is not a very difficult problem. It was a long way to answer it. Pf wes. Burke. What was the occasion of the magnetic tape being made from the Dictabelt? Mr. Barger. I don't know. It was a fortunate one. Mrs. Burke. -Was it the Warren Commission? Mr. Barger. I don't know because Dictabelts don't like to be played very often or they become distorted so - “whoever took the precaution of the Dictabelt early on was doing us a great favor. If we had had to do this from the Dictabelt we never would have found anything, I am quite certain. I mean as it now exists. It has been played too often. Mr. Blakey. What I am giving you is my impression nd don't rely on it as precise. This material was in the possession of the Dallas Police Department. There was a special unit down there established to investigate the Kennedy homicide and it became the repository of all the evidence and all of the records of the Police Department obtained in connection with the Kennedy assassination. It has been and was largely ignored by everyone. The FBI and the Archives, it was only after we.had developed the easy relationship with ALDERSON REPORTING COMPANY, INC. Page 106
34 » =S5 = nN Z 6 iQ es . x 7 x S 8. N no) a 9 Z g & 10 Z a 1M 4 g 12 a: oe.” Fe Nn 2 14 e fe S 15 fx [aad J 16 MN B17 is} jaey mh 6 O18 c F419 2 20 21 @ ” 23 24 25 Docld: 32266686 107 the Dallas Police Department that we were made aware of it and indeed of the records. Those records were obtained, the Dictabelt. It was rather late in our investigation that we found it. I would rather have had this thage or ede months ago. He said he could not find a tape for the longest time. Furs. Burke. When do you do the experiment? Mr. Blakey. We hope to do it at the end of this month. There are other things before final decisions can be made. Chairman Stokes. There is another test the doctor has indicated they are running the first part of next week. If there is nothing further, Dr. Barger, we certainly © appreciate your having appeared here today. This has been a very interesting, fascinating experience for us to listen to you, and you have our appreciation for your appearance. Mr. Barger. Well, thank you very much. I appreciate being here on the project, it seems like quite a sensible one. Mr. Devine. And kind of fascinating from your standpoint, too, wasn't it? Mr. Barger. Needless to say, it is not the sort of thing that one can publish, and scientists like to do that, but nevertheless it is very unusual. Chairman Stokes. Nothing further? Mr. Blakey. Nothing further. Chairman Stokes. There being no further business to come before the committee, the meeting is adjourned subject to ALDERSON REPORTING COMPANY, INC. Page 109
35 the call of the Chair. 2 ui. © Q > re) 5 a N $ 6 e ~~ N S 8 N ) a 9 Zz = & 10 Z a 11 2 g 12 . e:” faa] Nn 5 14 fan] . 2 15 jc] [oa] . 16 io 2] E17 ica} foot 5 618 jan} a F419 Es 20 21 eo °* . 23 24 25 Docld: 32727666586 Page 110 H fithereupon, at 3:15 p.m., the committee adjourned, subject to the call of the Chair.) @ ALDERSON REPORTING COMPANY, INC. 108