@cmartenson I just published the latest update to my TDOA analysis, and I think I’ve made a compelling technical argument for the precise location of all 10 shots. I’ve put a huge amount of effort and hours to get to this point, so I would really appreciate it if each of the participants in this forum topic would take the time to watch the video and provide feedback, if any.
And thank you @vt1 for providing the formula for calculating the crack-boom time difference. Once I implemented that in the model, everything fell into place.
I watch them, Greg, all of them. I greatly appreciate all the hard work you put into this, and especially for posting your videos. That sets you apart. This latest video is by far your best yet. Kudos!
To test that theory, I would would need to modify the model as follows:
Choose alternate location (such as wall_vent)
Use podium mic crack-boom times to determine velocities for those first three shots as if they were fired from the alternate location
Apply appropriate crack-boom corrections to the recorders. For example, if the shots came from the wall_vent, the crack-boom corrections would only be applied to TMX and DJstew since the police cruiser was behind the line of fire and would not hear the crack.
Ground truth would be roof shooter @ shot 4 (unless you don’t think that shots 4-8 came from there, which would add another layer of complexity to the situation).
The second window from the right of the two-story building would be nice (it should have been open).
So you don’t select certain types of guns and ammunition, but get values for which you then have to see if there are suitable gun-ammunition combinations?
And I’ve just been looking at the wall_vent. To achieve the crack-boom times recorded by the podium mic of 221, 217 & 212 ms for shots 1-3, a rifle firing from that closer position would have needed to have bullet velocities at 140 yards of 3260, 3150 and 3030 fps. To achieve such velocities at 140 yds, the muzzle velocity would need be over 3500. Is that even achievable? I don’t think I’ll pursue the wall vent any further.
As far as the second floor window, that position is so far off the actual line of fire that I’m sure the timing data couldn’t possibly support it.
@daniel59, what is your technical reasoning for why you think shots 1-3 came from a different location?
The ER physician who tried to rescue the life of Corey Comparatore was Dr. Jim Sweetman. In this CBS interview he recounts his deep affliction when after a short while armed men in military look tapped him on the shoulder and told him to stop.
edit: not military man, but “the biggest Pennsylvania State Police officers he had ever seen”. There is some other video clip elsewhere showing how they took him from the hands of Dr. Sweetman and hauled him away like a shot deer.
edit: it was this clip, and officers in military look were also present. No stretchers, but some emergency personel belonging to a police unit can also be seen.
-79.97048784435141,40.8582313115371,4.3
respectively longitude and latitude in degrees, altitude in meters above ground. if you need above sea level, you can add 408m
there is a technical drawing that was annotated with the heights. I printed it out but do not have the digital version handy. it says that the top of the vents is at 9 ft 10 inches from the ground level, and the vents are about 12x12 inch squares
as you know, there is some discussion about the ground level values, but you can use 408m above sea level as a start if you want to show them in google earth. if you wish, I can give you the coordinates lon,lat,alt if you tell me which vent you want using the windows as reference… the leftmost window is window 1, the rightmost window 5
a couple of days ago, I annotated the heights of the green area around building 6…
I can imagine that the depression causes some echo nightmare…
I use a muzzle height of 1.7m for the SWAT officer that fired shot 9.
from my point of view, chances are very high that this same SWAT officer also fired shot 10.
absolute height of the muzzle of this SWAT officer is 412.00652m above sea level when using google earth as the reference
-79.97050189336855,40.85671273398304,6.0, so 6m above ground
Thanks for your questions. I am working on something now that may answer some of your questions–I started with the DStew video but am going to apply this to Trump’s mike also since some of the snicks step on some of the booms. The bullet shock wave consistently has its primary energy around 9 kHz. The onset of the boom of the gun, however, centers on a few hundred Hz and resembles what in radar is called a “chirp” with energy spread in a region around a center frequency. Given the difference in frequencies between the bullet and the gun report, I was able to apply a low-pass high-rolloff filter to the DStew video and completely unmask the “boom” signal. I will make a more detailed post with images, but the primary findings here for the DStew video are:
that after filtering above 1 kHz, for the first three shots, the center frequency of the residual “boom” is 456-459 Hz, and for the last five shots it is 282-306 Hz (wildly different between the groups)
that the DELAY from the onset of the shock wave to the onset of the report (which was masked before) is different (25 msec for the first three, 13-16 msec for the second five shots). This is hard to understand from DStew’s position, so that is one I am thinking about.
Because the boom was masked before I applied this filter, I have now been able to more accurately re-time the booms for DStew. There is still a disagreement with the podium and a single-shooter position, but smaller. But now we also have the snick-to-boom discrepancy thrown in.
I disagree with others’ conclusions that triangulation converges to a single shooting location. There is a lot of uncertainty thrown in here, and they are also using the police cruiser timing, where I 100% believe that to be faked.
Thank you for the update Greg. I have a few questions:
Where did you find snick times for Ross and the Police Cruiser? Neither was in front of your shooter location and a shockwave should not have propagated to them.
Where did you find boom times for DStew? The booms are masked in the recording. This problem also exists for some of the TMZ shots.
Can you share all of your snick-boom measurements with us?
The assumption I have worked with is a shooter shooting through a vent could be virtually anywhere in the ceiling behind the vent and on the shot line. Many of your solutions do place shots 1-3 grouped closer and shots 4-8 grouped closer. Why can this not be due to a shooter positioned closer to below the peak of the roof in the overhead space, with a scope view through the vent?
The police cruiser audio shows remarkable agreement with the podium timing for a single shooter position, and virtually identical audio signatures for all eight shots. Given how much you have looked at the data, have you seen this uniformity of audio signature among the eight shots replicated in any other source? I have seen anything but. To me the cruiser is a strong outlier, and given the length of time it was in sole possession of the government, makes it highly suspect.
@howdoiknowthisinfo thanks for providing the altitudes I was looking for, but I’d like some clarification, please. There is an “elev” number provided by Google Earth down in the lower-right of the screen. Is that m above sea level? The numbers on your annotated photo are all 2 to 3 m higher than Google Earth. I assume your numbers are more accurate, so does that mean that the Earth numbers are just a rough estimate and not a measured value? I would expect Google to be using surveyed data.
Do you know the absolute height for the South Barn? Earth says the ground elevation there is 407 m, but if that value can’t be trusted …
You didn’t mention the height of the podium mic. I saved a chart that someone here made that shows “trump’s height” as 412.86. Would that be a good number to use for the podium mic?
