Audio Analysis Is Most Consistent Two Shooters At Trump Rally

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Chris,
I believe it would be very interesting for you to convert echo time for each microphone location to feet based upon the speed of sound at the Butler location that day. For each microphone location draw a circle with radius of that distance on a plot map of the rally. Each circle should show all of the possible buildings of the sound reflection. Intersected circles should define the reflection site and could help determine if multiple shooter locations were involved.

As an electrical engineer, the “Squelch effect” on sound tracks, is the result of a circuit in the preamplifier called Automatic Gain Control {AGC). The AGC circuit maintains a good signal to noise ratio and prevents overdriving the amplifier and speakers.

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Forget the moving video, focus just on the Trump mic. Differential audio delay of .007 seconds implies shots 4-8 were ~15 feet closer to Trump than shots 1-3. Since Crooks was seen in D Stewart video with his head sticking up right at the roof ridge just before the first shot, if it was Crooks who shot 1-3, then for Crooks to shoot 4-8 15 ft closer he’d have moved way over the ridge onto the visible side of the roof - nobody noted this, Stewart video does not show this, would have been absolutely stupid of Crooks to become so visible. Conclusion: Crooks cannot have taken all shots 1-8.

This argument does not depend on making any assumption about the speed of a moving videographer.

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The challenge with this idea is that the delay of the echo, to be converted into feet, would have to make a lot of assumptions about the distance between the shot and the reflective surface generating the echo before its arrival at the microphone. The echo travels from gun to surface to mic. Without knowing the distance between gun and surface and between gun and mic, you have one data point (echo delay) and two unknowns.

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I ruled it out based on audio and ballistic evidence. The distance to Trump’s stage was about 730 feet from that tall building. Given the snick-boom delay of .22 seconds (or .213 for that matter), from that distance the implied average speed of the bullet is only about 1880 ft/s. In contrast, ballistics data on multiple 223 rounds have the slowest 223 round averaging about 2300 ft/s over that distance, 30% faster than the data implies on the assumption of a shot from 730 feet. This huge mismatch rules out a shot from anywhere modestly close to 730 feet.

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The .007 second difference in the chart is the difference between shot 1 and shot 3, not the difference between shot 3 and shot 4.

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Sorry to be repetitive but I put this in the thread that was shut down.

I did some math to generate the locus of points where an unknown sound could be coming from if you have:

  • one sound of known location
  • one sound of unknown location
  • two microphones both stationary and of known location
    And the only data needed is just the time difference between the two sounds as measured by different mics. Just the exact time of each report. No click-boom or echoes needed.

At the Desmos link I have one mic fixed at the podium (but would be easy to change), the position of the other mic can be moved. And the difference of the two time differences can be dialed in. You get a dashed line: the unknown sound could be anywhere along that line. More mics = triangulation.

It should be possible to locate 123 vs 45678 vs 9 vs 10 if there are several recordings from known locations.

image
image416×546 31.2 KB

Link to interactive graph on Desmos.

My original post is here.

trump-shooting

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I think in the 13 second of this video we can see the 2nd shot been fired. The white blob that appears exactly at Crooks position and this may actually be the gun fire.

Video - Dropbox

These are the 13 frames where the white spot appears in 11 off them. That is 0.36 seconds of the white flash. Is this consistent with a gun fire flash?

image
image1129×1209 127 KB

At the position of the footage (top of the middle bleacher) it was certainly above trumps head, so it should have visual of Crooks.

The sound of the 2nd shoot appears in the middle of the white flash around frame 8. That is 0.23 seconds of delay from the appearance of the white flash.

In the next 10 frames on second 14 it changes the color black. That might be Crooks.

Can someone check when the audio of the 2nd shot appears exactly???
Can someone make that spot still in the video???

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THERE WAS A 2nd SHOOTER
Based on the timing of the “sonic boom” and report of 1st shot at Trump’s mic — time difference 0.22 secs — the muzzle of the gun had to be 417’ ± a few feet from Trump. That does NOT get you to where Crooks was. It gets you EXACTLY to the front edge of that building.

Given that the 1st floor windows were too low to shoot line of sight to Trump, and those windows seem to have been “cleared” by law enforcement — the DJ video shows that — I think 2nd shooter was in the ceiling of the building that Crooks was on, approximately at but several feet above the height of the top of the 2nd window from the right.

There seems to be something wrong with your calculation. You listed 1203.6 ft/sec as the speed of sound, but I calculate it at somewhere between 1161 and 1168 ft/sec.

Speed of sound in dry air = 331.3 + .606T (m/s). The temp was 93ºF at 6pm on 7/13 or 33.9ºC, so that yields 331.3+.60633.9 = 351.8 m/s in dry air.

Assuming the humidity was between 50 and 100%, you can apply the correcting factor (1+.0124*H) so that would be 1.0062 at 50% and 1.0124 at 100%). That yields 351.8 * 1.0062 = 354 or 351.8 x 1.0124 = 356.2.

Converting to fps that gives a range of 1161.4 to 1168.1 m/s which is SIGNIFICANTLY (3.5%) less than your estimate.

Based on your timings of 0.22 secs between sonic boom and report at Trump’s mic, and using the 50% humidity, and the assumption of 3000 fps muzzle velocity for 5.56 NATO rounds out of a standard 16" barrel AR-5 platform, that implies a distance of only 417 ft from Trump to muzzle. From Trump’s location, that gets you to the second window from the right on the ONE-story building that the shooter was ON TOP of. But it doesn’t get you to shooter’s muzzle location which was approximately another 45 ft away from that at the apex of the roof. Furthermore, that window is in a direct line from shooter to Trump.

Unless my calculations are wrong, this implies a shooter from the ONE story building, 2nd window from right.

Also, on the videos I have seen, and you have showed, it is the 1st shot that hits Trump’s ear, as he immediately grabs his ear, sees the blood and drops down before we hear all the subsequent shots.

You also showed a cell phone video showing that shooter’s shoulder did not move at all upon 1st shot firing. That also clearly implies he was not shooting at that moment.

Obvious other questions are where are the shells? Where are the bullets? Where are the rounds shot by counter snipers? Where are the rounds that hit the shooter?

Google Earth overview

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People keep using the .22 seconds number, but in Chris’ video it says this is source 2, which is an unknown distance from Crooks’ position. Only the stage mic can be used for “snick-boom” type measurements based on the stage distance. Even then, it is a lousy measurement as it depends on the shooter’s aim.

As shown below, the Mach no. (and resulting Mach cone) determine when the sound of a passing bullet arrives at a microphone. At Mach 2.45 (which is reasonable in this case), a bullet passing only two feet from the mic will be 4.5 feet downrange when the “snick” reaches the mic. A bullet passing 8 feet from the mic will be 18 feet downrange when the snick reaches the mic. And it seems shots 4-8 were a bit wild, so go figure.

Mach cone graphic
Mach cone graphic1567×1150 133 KB

Now audio source 2 is way off the bullet path (40 feet? maybe, who knows?). Not only are they way closer to Crooks, but the bullet will be 100 feet downrange when the snick reaches the mic, and the boom is 40 feet closer to them by then…just saying, these types of measurements may not be as helpful as you think. Concentrate on the booms.

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Real important Chris, the distance from the Mic to the “Mach Cone” is important and might account for some of the variation. Good point.

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But how have you determined the caliber?

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Request: Please run your calculations at the extremes of both ends of all variables. That will give us a “range” of extremes of how close or how far away the assassin might have been.

E.g. recalculate using your numbers but the extremes of speeds for 5.56mm or .223 winchester. Then recalculate using extremes of speeds of sounds, high and low, etc.

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Turns out what I was describing before is “Object Tracking using Time Difference of Arrival.”

This analysis was done for shots 1 through 10 by YouTuber using 4 microphones:
@greg_nichols
" Trump Rally Audio Analysis: Counter-Sniper Location Revealed!"

He concludes the first 8 all came from Crooks’ position and that shots 9 and 10 were from just north of the audience very near a red farm equipment. However the first 8 shot locations drift quite a bit, I think due to the movement of the phones.

The first part of his video is analyzing snick-boom; but then he gets into the arrival time which is what I was hoping for.

This could still be confirmed by other investigators; by finding other recordings; perhaps fine tuned by factoring phone locations that changed between shots.

I don’t think this rules out other locations that are very near Crooks position.

In a pinned comment, he said he found that the red farm vehicle shown at the end of the video is a Case 8230 harvester. The top of the cab is 29 feet off the ground and would have made an excellent vantage point.

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I just posted this in a different thread regarding the ESU officer who most likely fired shot 9 and from where. He was definitely paying attention to building 6.

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Supersonic cracks are very useful for determining direction of shooter if you have three or more microphones. Further, the direction is even better if you have them in a plane perpendicular to the bullet trajectory. They are not good for determining range other than to provide a time difference between crack and boom of gun report. Shooter location is best determined from direct line of sight gun reports. The number of data points for gun reports depends upon whether you want 2-D or 3-D solution for location. And the microphones need to be distributed to cover all dimensions. The problem here is that microphones are mostly distributed in a 2-D geometric plane and won’t be able to help with elevation. And worse, the microphones in which we have data are mostly along the same line without much of a second dimensional separation.

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VT,
Gun flash is too fast sometimes to be captured in video. Moreover, the flash would be larger and directional with the flash suppressor instead of a dot. The white dot is most likely the reflection off the lens of his red dot scope that happened to glint some light. Any relation to a shot may be the cringing factor of the shooter reflexing to the loud reports nearby.

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Kwaka,

Thanks for the pointer. I am new here. Now I need to figure out how to get the audio data I need stripped from these mp3 files and must figure out locations from the video. I don’t know if someone has done this before. Normally, engineers on my staff take care of these details but I am not at work for this.

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The audio files have been trimmed up by another member here:

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Please be more specific about what you want and I’ll provide it.

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One thing you have missed in your speed of sound calculation is the elevation or altitude at Butler PA at 1043 feet. I don’t know exactly how much of a difference it makes, the air does get thinner the higher it gets.