In December 2021, ABC7 News in San Francisco aired an outstanding documentary on the JFK assassination titled
JFK Unsolved: The Real Conspiracies that includes valuable segments on the acoustical evidence. The documentary was written and produced by Emmy Award-winning investigative journalist Dan Noyes, who works for ABC7 News. Noyes has also won the Journalistic Integrity Award from California Attorneys for Criminal Justice. The documentary focuses on the research presented in Dr. Josiah Thompson's 2021 book
Last Second in Dallas, but it also includes important segments on other research, such as Dr. Doug DeSalles' wound-ballistics tests.
The documentary contains excellent segments on the acoustical evidence, especially the final segment, which discusses the new research done by BBN scientists Dr. James Barger and Dr. Richard Mullen. The segment does the best job I have ever seen of explaining one of the key findings of the new acoustical research, namely, that the Decker "hold everything" transmission is an overdub, not crosstalk.
Here is the transcript of that segment from the documentary's transcript:
NOYES: Thompson next revisited the sound of gunfire captured by that open microphone on a Dallas police motorcycle tuned to Channel 1.
In 1982 the National Academy of Sciences disputed that recording. They compared it to Channel 2 of the police radio that day and ruled what sounded like gunfire actually happened 60 seconds after the assassination.
THOMPSON: That particular report has been believed for about 30 years. It was wrong it was wildly wrong.
NOYES: For his new book Thompson contacted the scientist who initially confirmed the recording as authentic, that the motorcycle's open microphone caught the sounds of the assassination. James Barger led the acoustics recreation in Dealey Plaza in 1978 for the House Select Committee on Assassinations.
BARGER: I hate to see what I know darn well was well-documented, good science cast aside by, well, bad science.
NOYES: Barger happily came out of retirement after Thompson's call and worked for the past several years with an old colleague, engineer Richard Mullen, analyzing the radio recordings.
BARGER: And he found out, yes, the Channel 2 tape had been over dubbed -- it had been cut -- by measuring the hum frequencies very carefully.
THOMPSON: If you have several hum frequencies this meant that it went through several different electronic devices in in becoming what it was.
NOYES: The Channel 2 recording was not an original as the government contended, and someone spliced or edited the tape. The National Academy of Sciences made a mistake using the Channel 2 recording to refute the sounds of gunfire heard on Channel 1. (JFK Unsolved: The Real Conspiracies, 1:05:27 to 1:07:21)Dr. Barger explained the overdub evidence and its implications in plain language to Dr. Thompson:
The odds that Channel 2 would have two hum frequencies are very small. It’s a strong indication that the Channel 2 tapes came from a second-generation Audograph disk. Therefore, two independent actions were responsible for those two hum frequencies. It is wholly unlikely that two additional and independent actions on Channel 1 could reproduce the exact same hum frequencies produced by two independent actions on Channel 2. The fact that both of these hum frequencies were recorded on Channel 1 is proof that the HOLD family of crosstalk was overdubbed onto Channel 1. (Last Second in Dallas, 2021, p. 547)Here is part of Dr. Barger's explanation of some of the findings of the new BBN research in his appendix titled "A Quantitative Analysis of Crosstalk Found in Audio Recorded During the JFK Assassination" in Thompson's book:
Five instances of crosstalk and one simulcast are heard within a period of about five minutes at the time of the JFK assassination when listening to audio records of the two Dallas Police Department (DPD) radio communication channels. However, when the two surviving audio channels are aligned in time at the simulcast, none of the five crosstalk events align in time—none are synchronous. A committee appointed by the National Research Council (NRC) posited that one crosstalk event (“Hold everything” [HOLD]) did nevertheless align on the basis of hypothetical Channel 2 data logger pauses. Moreover, the survivors of this committee concluded in 2005 that another crosstalk event (“I’ll check it”) was not even crosstalk.
This paper discovers crosstalk synchrony-—i.e., recorded simultaneously in real time—-by using the idea of correcting the playback times of dispatcher-voiced annotation times so that they synchronize with the corresponding original spoken clock times. Hum signal frequencies found in both radio channels, including two frequencies that are common to both, inform the deduction of recording histories of all crosstalk events. It is found that two events, “I’ll check it” and “I’ve got” were likely recorded onto Channel 1 from Channel 2 audio in real time as crosstalk during the assassination. The other three events, HOLD and two others, were overdubbed onto Channel 1 from Channel 2 during a later session. Consequently, the HOLD family of crosstalks cannot be used to infer the causality of anything recorded in real time. . . .
The actual overdubbing was probably inadvertent. The HOLD family [i.e., the Decker "hold everything" transmission soundwaves] share a robust signal-to-noise ratio on Channel 2. Their corresponding signals on Channel 1 are very weak—-HOLD itself is near hearing threshold. Therefore, the Channel 2 noise level that would have been overdubbed would be well below the Channel 1 noise level and cannot be identified. The effect of this overdub probably causes the presence of the HOLD family on Channel 1 to be an artifact—-the result of the multiple tape copies and dubs made to and from multiple machines in the first days by technicians at the DPD and FBI and attested by the intricate and odd assemblage of hum frequencies found by Richard Mullen. (Appendix A: A Quantitative Analysis of Crosstalk Found in Audio Recorded During the JFK Assassination, Last Second in Dallas, 2021, pp. 571-572, 589-590) Finally, a word about my qualifications when it comes to acoustics, such as they are:
You claim to have had acoustics training although I don't know how your particular training applies to the evidence in question.
I "claim" this because I did in fact receive some training in basic acoustics as part of my training as a military intelligence signals technician in the Army. My training included instruction in radio wave propagation, RF theory, the electromagnetic spectrum, emitter characteristics, geolocation/direction-finding methods, soundwave modulation (AM vs. FM vs. PM), the effect of weather conditions on radio waves, the use of triangulation in geolocating the origin of a radio signal, and multichannel technology.
For those who may be interested in seeing verification of this training, below is a link to my NSA National Cryptologic School transcript (for obvious reasons, I've blacked out my SSN). "SIGINT" stands for signals intelligence. The transcript documents that I completed the following courses (among others): Low VHF SIGINT Operation, Basic Satellites, Introduction to SIGINT Reporting, Basic Multichannel Technology, and Principles of Collection.
NCS TranscriptI should add that as a SIGINT technician, I actually used signals-interception and direction-finding equipment and actually performed signals interception and signals geolocation.
And, as I've also mentioned, for about three years I worked as a technical editor for a Navy command that dealt with air and missile defense, and in that capacity I edited manuals that included sections on signals detection and direction-finding equipment.
However, I once again repeat that I do not claim to be an acoustical scientist. My acoustics training and experience were far below the training and experience of an acoustical scientist. But, I do know a lot more about acoustical science than your average Joe.
