The impossibility of the “assassination attempt" audio

Waveform of the first gunshot at the campaign rally of candidate Trump on July 13 in Butler, Pennsylvania. The bullet produces a sonic boom (arrow). The waveform immediately preceding the sonic boom is from the speech of candidate Trump.

The sound of gunshots at the campaign rally of Donald Trump was recorded by the microphone on the stage. That recording is impossible. It is contrary to all prior studies of the sound of supersonic bullets.

Supersonic bullets produce a sonic boom. This explains why the use of silencers are not effective with such firearms - the bullet itself produces a shock wave. In a Quora discussion, the sound was described as a “bloody loud crack”. More precisely, one study found that 5.56 mm bullets traveling at supersonic speeds produce sounds in the range of 149 to 154 dB at a miss distance of 2 meters.¹ On the other hand, the sound level of speech is estimated to be in the range of 70 to 88 dB measured from a distance of 1 foot.

However, the audio recording of the event is not even remotely consistent with the known difference between the strength of the sound of the gunshot and of a person’s speech. Conservatively, there should be a 61 dB difference between the strength of the gunshot sound and a person’s speech. A 61 dB difference in sound level is equivalent to a ratio of the amplitude of the two waveforms of 1122.² However, in the audio recording of the event, the ratio of the amplitude of the sonic boom to that of candidate Trump’s speech is approximately 2 - as seen in the figure above. The audio recording is clearly impossible implausible.

The absence of a visible wound on the candidate’s ear was evidence enough that the assassination attempt was a hoax. However, that is only scratching the surface of the fraudulence of this event and the degrading deception of the country.

UPDATE (9/8): It is possible that processing of the audio - by audio limiter - will reduce the amplitude of loud sounds. However, the amplitude of the waveform the bullet shock wave should be greater than that of any other sound. That is not the case for the audio of the “assassination attempt”.

UPDATE(9/8 2nd) Title of article changed from “The impossibility of the ‘assassination attempt’ audio” to “The implausibility of the ‘assassination attempt’ audio”. It is possible, but unlikely, that the 150 dB shock wave produced by the bullet would be suppressed to a level below that of a voice.

UPDATE (9/11) The title is reverted to “The impossibility of the ‘assassination attempt’ audio” after discussions on Reddit. Current audio technology requires tuning of the audio system for the expected maximum sound level.

UPDATE (9/16) Presentation on technical aspects of recording of AR-15 sound. Discussion of settings of microphones at 2:05 and example of “clipping” distortion that occurs when the bullet/gun is to the microphone at 5:25.

1.

Sound Pressure Level of supersonic bullets. Measurements shown in blue are for a miss distance of 2 meters.

The above graph represents the sound pressure level in log of peak pressure in [atmospheres]. That unit of sound pressure level is interchangeable with decibels. The conversion steps are as follows: (a) Apply the formula A=10^S to find the peak pressure in atmospheres. S is the sound pressure level in units of log of peak pressure in atmospheres and A is the peak pressure in atmospheres. (b) Apply the following formula to convert from units of atmospheres to Pascals: P = 101325 Pascals/Atmospheres X A, where P is the pressure in Pascals and (c) Apply the formula for sound pressure level in decibels: D=20 log(P/0.00002 Pascals), where D is the sound pressure level in decibels.

2. Conversion from differences in sound pressure level to ratio of sound pressure at https://w1.mtsu.edu/faculty/wroberts/teaching/log_3.php