I think offtheback was using the audio track that comes from a mic that we know is inside the car because we can hear the A/C running. When we’re sitting in the cabin and hear gunshots, yeah, they will be muffled, but that won’t mute the high frequency stuff we were already recording.
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(By the way, I think I have not heard the Otto-engine which runs with petrol. I guess this car is powered by rechargable batteries.)
@vt1, what @brian60221 said. We are looking for all of the ambient noise in the cabin and asking where did it go? For instance, here is the signal at a random place in the space between shots 3 and 4, and I have filtered out everything below 8 kHz so we can focus on the high-frequency noise:
Here is a similar plot from in the middle of shot 9. Plenty of high-frequency noise still there.
Now here is a plot during shot 6. For over 1,700 audio samples, there is no high frequency noise recorded at all. At all. This is beyond unusual, it is unexplainable.
This can only be a f@#k up by the people who assembled this.
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Statistically unusual I would say. 
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It isn’t even the same for all of the shots. Some have smaller but still statistically improbable blank spaces. Some are just notably sparser but no huge gaps.
My guess as to what happened here: They first cut out all of the “real” shots with slightly different timing. This also cut out the noise. They then added the pristine shot waveform they wanted to use (eight times) at the spacings they wanted. Then they added some noise to mask the process. But the noise wasn’t the same as the real cabin noise. And in some places, they didn’t get it everywhere they needed it. Not easy to see if you are looking at the whole composite signal, so out the door it went.
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I sent an inquiry about the chain of custody of the videos (how exactly they got from the PD’s systems to Dropbox) and will let everyone know if I hear back.
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.223/5.56mm the difference is no big deal. Even a AR marked .223 Rem, might have a 5.56mm spec chamber.
I’ve got a bachelor’s and master’s degrees in math. They are old degrees, and I am getting old. I’ve forgotten 80% of the math I’ve learned, and probably dropped 30 IQ points from when I was 20. When you say “Newton’s method” I think “hmm, I studied that once…”
I was able to reproduce the final equation greg_n had in his video by treating it as a basic calculus problem: take the derivative of the time needed for the sound to reach the microphone with respect to D1, find D1 where that derivative is zero, and plug into the time. I’m rusty enough that took an embarrassing amount of time.
I think I can figure out equation 1. Is “a” a deceleration force? t1 doesn’t seem to be defined or marked in the illustration. I’m guessing D1 is the distance between point M and point 1 and t1 is the time the bullet takes to travel between those points.
I honestly can’t figure out eq.2
It would be really helpful if you could give an example using fairly realistic numbers in those equations.
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I read somewhere that if it were barreled for one of the cartridges both could be used, but not if it was barreled for the other. I don’t recall the more limiting barrel design. To be clear, I don’t believe it prohibited from firing the other cartridge, it just introduced some risk you wouldn’t want to take using it.
Hi offtheback,
17 days ago, I think it is just about the day all these body cam videos came out, I got into an argument with intolerance. I was claiming not to hear echoes with the first 3 shots and shots 4 – 8 with echoes. This is what Chris was arguing from the beginning and what convinced me to start joining this forum.
Then intolerance pointed out to me that on newest video all 8 shots had echoes. First, I did not hear any echoes on shots 1 -3, simply by listening to Audio and I claimed he had found a new source from the side of the building. Maybe I desperately wanted to believe and confirm that shots 1 - 3 had no echoes (similar to what you told Greg)
But he insisted that all 8 had echoes. I got the feeling he knew much more than me on this topic, but why, the video just came out?
Not being a audio specialist like you, I did however simply extract the audio and had a visual inspection of each shot and the first thing that came to my mind was the same you also are claiming, namely these 8 shots are modified, just like the vents in front of the wall of building 6 are covered up with paint. I had to stop this conversation, and I hoped for somebody like you to professionally debunk this audio. But finally, I would like to know, do you hear any echoes in this recording at all?
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People fire 5.56mm ammo in .223 Remington marked rifles all the time. It is possible it might cause higher chamber pressures. I would be more concerned if it was a bolt action rifle vs a AR type rifle.
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.223 caliber is a lower pressure caliber of near identical dimensions as 5.56x45mm.
5.56x45mm is a NATO chambering of higher pressure than .223.
Some older rifles were chambered only in .223 cal and caution against using higher pressure 5.56mm. In this respect, there is a 1-way compatibility, a 5.56mm rifle can fire both whereas it may be unsafe to fire 5.56mm in a rifle chambered for .223 cal. I bet many people ignore the caution without problems but it is unwise as the higher pressure 5.56 NATO might rupture the chamber and grenade the rifle.
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Some people used to warn about firing 5.56mm in a Ruger Mini-14 marked .223 Rem. But later Ruger came out and said it is safe to fire 5.56mm in their rifles.
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I want to make sure we’re on the same page. Is this what you’re referencing? I can try to get a better shot of it.
Hi Roger,
All 8 shots are for all intents and purposes identical in the cruiser audio. The echo starts about .1 seconds after the shot and peaks about .15 seconds after the shot. The echoes are weird, though, as they have a lot of higher frequency content that isn’t in the initial report. Here I show the frequency spectrum of the initial report and the echo for one shot.
The echo has a higher-pitched peak frequency than the original shot. The long fat tail on the echo spectrum means that if this is real, the cruiser glass isn’t muffling the shots too much. But the report itself has almost no energy above 2000 Hz while the echo does.
The only physical world explanation that even starts to address this is that the echo is of the bullet sonic signature that bounced off something in front of the shot–I don’t know what that would be, DJ Stewart (joking)? Even he was too far away for that.
But what really happened is the report inexplicably has no high-frequency content. It doesn’t match the echo or the noise spectrum of the rest of the audio.
So yes, there is an echo. Does it actually go with the report it follows or not? Seems like another potential contradiction with this source.
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Hi Offtheback,
Just for your information, I made a frame compare between the video I downloaded from the TMZ homepage on Friday, August 23 and the one that is still online at scoopernews. They are a perfect match (with one frame offset) Here is the link to this video:
So, you can kind of travel back in time and download this video, which was still online on the TMZ homepage just last Friday.
Here are the screenshots from the Scoopernews version:
For all of those who do not know what we are doing here, we think that we have eligibly found evidence that TMZ has been editing the famous “Crooks on the roof video”, adding dynamics and enhancing shell casings.
If you don’t believe us, then go to the above webpage, download the “older version” of the TMZ video extract each frame of the first part of the video (not the whole video, because that will explode your harddrive with data 
) with a tool such as VLC media, then do the same with the video which is now officially on the TMZ homepage and when comparing with difchecker (free online tool) you will notice that eligibly small changes to crooks body has been applied to simulate the riffle recoil and to emphasize the casing…
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Yes, of course, I’ve already edited those posts to better explain myself and also that file. After your explanation that the AGRdifference values were already accounted for in the ground elevations I can understand how we had a failure to communicate. Also, please note that that file doesn’t mention AGRdifference, they are just lines I use for adding or subtracting values to the ongoing model without changing the original ones. On that particular file I typed the same AGRdifference values you use and noticed that the Crooks trajectory then happens to work, but I understand that those values, as you explained, are already accounted for in your ground elevations. I use those lines called extra to test out many values and many scenarios. I was simply interested in talking about it that particular scenario with you.
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I see this has allready been reported, but these are the last seconds of Crooks just befor he is taken out by the sniper with the 10th shot.
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