Philip Van Praag is an expert in audio and computer technology. After bachelor’s and master’s degrees, he worked at Bell Laboratories, Sandia National Laboratories, and Ampex Corporation. During those periods he furthered his studies at the University of New Mexico and at Stanford.
He was senior instructor in commercial audio/video at Ampex; technical services manager at Audio Consultants; technical head of automated data management at Hughes Aircraft Company; vice president of information technology at the American Heart Association; vice president and chief information officer at Applied Power; and director of information technology at R.R. Donnelley.
In the spring of 2005, Van Praag was approached by Brad Johnson, a senior international news writer with CNN. Johnson had read Van Praag’s book, ‘Evolution of the Audio Recorder’ and asked him to examine an audio cassette copy from the California State Archives of a recording made at the Ambassador Hotel in Los Angeles, the night of June 4-5, 1968, by a freelance Canadian reporter named Stanislaw Pruszynski.
On August 6, 2005, Van Praag began to examine the recording.
Since the cassette tape was of such poor quality, Van Praag, with Johnson’s assistance, was able to make his own recording of the open-reel recording at the Archives using state-off-the-art equipment.
The Archive’s copy had been in the possession of the Los Angeles Police Department until 1987, which had kept in a drawer or something since the FBI gave it to them in 1969.
Van Praag first completed several preliminary steps. He examined the entirety of the tape, including several seconds before and after the period of time in which gunshots were discernible. He compared it with other audio and video recordings made prior and subsequent to the gunshots, reset it to real time, analyzed Pruszynski’s movements based on television network video feeds, determined the positions of the recording equipment with respect to room dimensions and the shooting site. simulated recordings with like equipment. He conducted a first-level detailed analysis to characterize the gunshot sounds in both number and timing, and a second-level detailed analysis of the gunshot sounds to characterize the gunshot impulse trailing edge envelope data for frequency content. He then conducted field testing as a result of frequency content data findings for envelope characterization and a data pattern match comparison between field test results and the Pruszynski recording test results.
In these steps, Van Praag first realized that the FBI-copied recording, made from a Royal Canadian Mounted Police dub of the original, consisted of several non-contiguous segments. He corrected this problem using reference to the ‘prominent background nominal-60 Hz frequency content found throughout.’ He then used analog laboratory audio active-filtering equipment and other tools such as time interval elongating computer software and frequency domain spectrum analyzer equipment.
Van Praag then compared the tape with several other commercial and private audio and video documents to ‘validate’ the various sounds throughout the Pruszynski tape.
In order to reestablish the correct timing for the entire gunshot interval –– FBI declassified documents indicated the Bureau tried to correct an obvious speed issue with the RCMP dub but the attempt had been imprecise –– Van Praag synchronized the tape with broadcast recordings from just before the shooting. “This provided the basis for comparing Pruszynski’s movements to the sounds of his recording, and then to ascertain the correct timing of the shot sounds recorded as (he) walked down the stairs from the stage area and entered the corridor leading to the kitchen pantry... As will be described... another benefit of the re-timing would prove to be the re-establishment of correct frequency content of the gunshot trailing edge waveforms.”
Van Praag continues: “With Pruszynski’s movements known, together with dimensional data, information concerning the locations of Sirhan and Senator Kennedy at the time of the shooting, and accurate approximation of Pruszynski’s equipment, I was then able to begin examining the shot sounds...”
He then utilized equipment and tape identical or similar to that used by Pruszynski in order to recreate gunshot sounds to match sound characteristics, given the limitations imposed by the consumer grade products; he further dubbed the tape using a recorder similar to the one used by the RCMP for the original cassette.
At that stage, Van Praag then used analog test equipment and computer-based software to determine the number of shots captured by Pruszynski’s recording. He notes that ”Given the recording equipment limitations, together with the general noisy crowd environment, and Pruszynski’s distance from the area from which the shots emerged,” he could not be sure he had not missed one or more. However, “13 shots were identified.”
Let’s note that again: 13 shots were identified.
“It is possible that the total number exceeds 13, in view of the fact that loud screams emerged within seconds from the people closest to the shooting scene as they became aware of what had just occurred. These emerging screams and loud shouting may have obscured the capture of discernible additional shot sounds.”
As one might anticipate, within the thirteen shots, the spacing between at least two of them was extremely narrow. The two instances identified were 149 milliseconds between shots 3 and 4 and 122 milliseconds between 7 and 8. As further testing proved, Sirhan’s Iver Johnson Cadet 55SA could not have been fired rapidly enough to alone account for these groupings.
Van Praag then examined the ‘short waveform envelope’ of each shot. The trailing waveform ‘envelope’ for a shot is long relative to the short initial impulse sound created at the instant of firing. Such a characteristic is used by standard law enforcement tools such as ‘Shotspotter’ to identify gunfire while ignoring other easily mistaken impulse sounds –– firecrackers, popping balloons –– that humans might misidentify.
What he found was rather interesting: five of the thirteen gunshot waveforms presented at 1,600 Hz, a level not found in the other eight waveforms. This anomaly was found in one, and only one, of each double pair. As other tests revealed, this was not caused by echoes or other environmental circumstances. Van Praag then conducted field tests on two different .22 caliber revolvers of that era, an Iver Johnson Cadet 55SA, the same as the one Sirhan used, and a Harrington and Richardson 922.
The H&R 922 has identical class characteristics to Sirhan’s Cadet, with six riflings, a right hand twist, and a 0.054 inch land width mark. The H&R was also the same make and model owned at the time of the assassination by one Thane Eugene Cesar, a part-time security guard who was positioned just behind and to Kennedy’s right.
Van Praag ran a series of tests using these weapons in the approximate positions they were in or, in Cesar’s case, apparently in, when the shooting took place, with the Pruszynski recording device behind Cesar’s position but facing Sirhan. According to his declaration under penalty of perjury, here’s what Van Praag found:
“Analysis of the test data was conducted using the Steinberg Wavelab computer software, the same software used to initially identify the frequency anomaly on the Pruszynski recording. The results revealed that no frequency anomaly was found within the Iver-Johnson test fire data within the tested frequencies, whether recorded from the front or from the rear of that gun as it was fired. With the H&R 922, however, a frequency anomaly was found when analyzing recordings from the rear of that gun but not from in front of that gun. Further, the test results revealed the frequency of that anomaly to be the same frequency (1,600 Hx) as that discovered within five of the Pruszynski recording captured shot sounds.”
“From a preponderance of witness accounts, Sirhan was firing in a westward direction. Pruszynski, and the microphone he was holding, was moving in an eastward direction, toward the kitchen pantry, and therefore toward the source of the shots. That put Pruszynski’s microphone in front of Sirhan’s gun. As my field test results placed the second gun firing in a direction facing away from the microphone, therefore that second gun was firing in an eastward direction, opposite that of Sirhan’s direction of fire.”
Van Praag points out that the capacity to perform the tests he performs here, plus the capacity to perform other tests to the depth and with the degree of accuracy he was able to employ, were not available in 1968. Thus, no other analysis has been able to get beneath a cursory examination. There was no sophisticated computer program able to discern frequency characteristics from the trailing edge in the audio wave envelope created by the gunshots, thus there was no ability to recognize the individual frequency based acoustic characteristics.
In fact, until recently, judgments concerning gunshots were based on human hearing, which is manifestly inferior considering that the human ear is generally unable to distinguish gunshots from other ‘impulse’ sounds, unable to identify and count the number of rapidly occurring gunshots, never mind evaluate their frequency content so as to differentiate between gun makes and models.
The methodology used by Van Praag is the same as that now used by countless police jurisdictions throughout the country. It is state of the art. It can separate and identify individual shots and discern their particular characteristics; it can assign shots to different weapons.
Philip Van Praag’s sworn Declaration under penalty of perjury was submitted as part of an appeals brief filed last November 20th, Robert Kennedy’s birthday. Sirhan Sirhan, who by all evidence did not kill Kennedy and who, most probably, was a hypnoprogrammed shooter, is seeking an evidentiary hearing because new evidence, including the Van Praag tests, makes it likely that he was wrongly convicted.
The government, naturally, opposes the petition. In its opposition, it cites several ‘experts’ who claim that they have listened to the Pruszynski tape and can hear eight shots and only eight shots. They do not use any of the available technology to get at the truth; they pretend that what they hear is good enough. The court will probably agree with them. The government, including the court system, does not want this murder pried open.
You can get a lot of rationalizations on this if you press them. It was a long time ago, what does it matter now? Sirhan was firing a gun, what difference does it make if he hit Kennedy or not since he meant to? Even if there was a second gun, whoever it was will never be found now, why rake up all that pain again?
There’s a wall of denial in this country that must be broken if America is going to survive. Crippling events do not occur in isolation, nor are they random. There is an evil which is still operative, probably stronger now than 44 years ago, and it will bring down everything if we continue to pretend it does not exist.
The Van Praag analysis of the gunshots in the hotel pantry 44 years ago destroys the official illusion of yet another lone nut. The murders of the Kennedys and Dr. King changed everything, and that is what they were meant to do. What a shame if the most remarkable experiment of freedom the world has ever seen should die because its people are too afraid to fight for it.
