I was hiking in the mountains and I yelled, "Hello". Right after that I heard four other people yell 'hello', one after the other. And here I thought I was alone.
Not only did four people answer, but they answered from four different distances.
The first thing wrong with your spreadsheet chartoon is that column 3 is defined as [Vel x + y in ft/s].
You do not define x or y.
You did not provide the exact rifle and barrel length.
As for ammunition, your chartoon specified .223.
In your spreadsheet chartoon, you specified 62 grain, but fail to say what or why. A popular 223 is Remington Metal Case, 55 grain. It provides 3239 fps.
Heavier 62 grain ammunition tends to go slower.
Do you think .223 American Eagle (Federal) FMJ 62 grain ammunition was used. It provides 3,020 initial velocity.
Do you think Remington Core-Lokt 62 grain ammunition was used. It provides 3100 fps initial velocity.
Perhaps an Ultramax FMJ 62 grain. That provides 2925 fps.
Perhaps a UMC Remington Flat Base Closed Tip 62 grain. That provides 3100 fps.
Perhaps USA (Winchester) FMJ 62 grain. That provides 3100 fps.
223 Rem. Full Metal Jacket Boat-Tail ammunition provides 3240 muzzle velocity, however, it is 55 grain, not 62 grain.
You did not provide calculations on the spreadsheet chartoon you created.
Your showing of two different times on the taxi driver video is pure bullshit.
You have no idea of the delay of the muzzle blast to the taxi, or the route the sound took. You do not account the time that sound is traveling at least 341 feet while the bullet is traveling.
You have no idea of where the sound turned around to come back to the taxi, or what path the sound took to return to the taxi.
Your echo chartoon describes itself as "Test for ECHO."
The formula you are making believe you are using specifies things that have nothing to do with taxi driver distant echo recordings.
"A microphone was placed near the muzzle to record both the muzzle blast and the sound of the bullet hitting the deer."
The recording for this method is of the nearby muzzle blast and the sound of the bullet hitting the target. In the Las Vegas taxi, you have a shooter 338 feet up, and the taxi is down, to the side, and out from the hotel. The gunman is around the corner from the taxi, and you have an echo of the muzzle blast coming back, from an unknown reflecting surface, via an unknown indirect route to the taxi which is at ground level and not line of sight.
Using Sound of Target Impact for Acoustic Reconstructions of Shooting Events
By: Michael Courtney, PhD, and Amy Courtney, PhD, Ballistics Testing Group, Western Carolina University, Cullowhee, NC
Key Words: acoustic, reconstruction, shooting
Abstract
The sound of a bullet hitting a target is sometimes discernable in an audio recording of a shooting event and can be used to determine the distance from shooter to target. This paper provides an example where the microphone is adjacent to the shooter and presents the simple math needed in cases where the microphone is adjacent to the target.
[...]
Introduction
With surveillance systems becoming more ubiquitous in society, the number of shooting events being captured on audio is rapidly increasing. The sound of a bullet hitting a living target is very loud, almost as loud as the muzzle blast. This allows determination of the distance between the shooter and target if the time of the muzzle blast and target strike can be determined from an audio recording. If the location of the target is known, this greatly narrows possible locations of the shooter.
Method
Deer were shot with a muzzleloader shooting saboted .40 caliber pistol bullets impacting at velocities typical of the .40 S&W cartridge (1350 fps for a 135 grain bullet). A microphone was placed near the muzzle to record both the muzzle blast and the sound of the bullet hitting the deer. The time recorded between the muzzle blast and bullet striking the target represents the sum of the bullet time of flight (tb) and the time for the sound to return to the microphone from the target (ts),
t = ts + tb = d/Vs + d/Vb
where d is the target distance, Vs is the velocity of sound, and Vb is the average bullet velocity over the distance.
Vb depends on the distance, because the bullet is slowing in flight due to air resistance. Consequently, this equation must be solved using a ballistic calculator [1] and an iterative technique where one guesses different distances and computes the resulting ts and tb until there is agreement with the observed total time. The ballistic calculator requires knowing the muzzle velocity, ballistic coefficient of the bullet, air temperature, relative humidity, barometric pressure, and altitude. Converging on a distance is not hard since the total time is a monotonic and nearly linear function of the distance.
[...]
Note: the formula cited above is NOT the one cited by you. It relies on a microphone close to the muzzle also being close enough to the target to pick up the sound of the bullets striking, not an echo of the muzzle blast returning from some unknown point.
These results show that it is possible to use an audio recording of a shooting event to accurately determine the distance between the target and shooter. In cases where the location of the microphone is different, the mathematical details are different, but the ideas are the same. For example, if the microphone is adjacent to the victim (such as a 911 recording might be), the equation for determining the distance becomes:
t = tb ts = d/Vb d/Vs
Directly above is the precise formula you have cited on your spreadsheet chartoon:
Did you have a victim in the taxi? This formula only applies where the microphone is close to the victim (the target).
The discussion continues,
If the muzzle blast duration obscures the sound of the bullet hitting the target, simple inspection of the sound waveform is insufficient. Filtering techniques or spectrogram generation might recover the time of the target hit [1], or determination of the target hit might not be possible. However, in cases where the microphone is adjacent to the target and the bullet is supersonic, the sound of the bullet hitting the target occurs first, so it cannot be obscured by the muzzle blast.
The last part is what The Health Ranger used, and what I expanded upon.
At page 6,
A significant weakness in the study is the placement of the microphone near the muzzle of the gun, an unlikely location in most forensic cases, except for possible reconstructions of self-defense claims where the event is captured on a recording of the emergency call, officer involved shootings where the event is captured on a duty radio or other nearby microphone, and cases where the distance to the target is important to determining whether a soldier followed the applicable rules of engagement.
The only audio recordings you linked to are that of the Taxi Driver. The Taxi Driver recordings are irrelevant to the formula you cite.
T2 - T1 is not the time some report traveled. It is time difference between the time of the bullet arrival report and the sound arrival report. If your dippy calculation were correct, and the bullet were subsonic, T1 would be larger than T2, the the time some mythical report traveled would be a negative number. T2 - T1 is larger or smaller depending on the difference between the speed of the bullet and the speed of sound. If the difference of the flight time of the bullet and sound at 1200 feet were .2 seconds, you would calculate (T2 - T1) the muzzle report traveled 400 yards in .2 seconds. The speed of sound would still take 1.06 seconds to travel 1200 feet. Regardless of what T2 - T1 indicates, the muzzle report will travel 1200 feet in 1.06 seconds. The difference between the two report times indicates the difference in the velocity of time and the velocity of the bullet. If the sound took 1.06 seconds, the distance was 1200 feet. With the known distance, the velocity of the bullet can be calculated. If the bullet took 0.2 seconds less, the bullet made the trip in 0.86 seconds. Your T2 - T1 calculation is complete nonsense.
Picking back up with your spreadsheet chartoon, you seem to have some fascination with the number 1.062.
This number is not directly relevant to the Las Vegas shootings, but is the time for sound, adjusted for specific conditions, to travel 400 yards or 1200 feet at 1130 feet per second. Nothing in particular is known to have happened where the bullet traveled 400 yards or 1200 feet at ground level.
1200 feet is not the distance from the window in Paddock's room to anything in particular identified with the case.
Las Vegas Shooting: Chaos at a Concert and a Frantic Search at Mandalay Bay
New York Times UPDATED 10:30 PM ET, OCT. 2, 2017
Here is where 400 yards or 1200 feet come from. It is an estimated distance between Mandalay Bay and the Harvest Festival stage, at ground level, based on a Google image.
Target shooting was invented to keep people like you distracted so you don't get bored and hurt yourselves.
If you don't already do it,start tomorrow! You owe it to your obsessive self.
In the entire history of the world,the only nations that had to build walls to keep their own citizens from leaving were those with leftist governments.
Where T1 is the last bullet sound and T2 is the last report sound.
1.07 seconds between T1 and T2 = 1208 ft.
1208 ft from the Mandalay Bay, per Google earth, puts us right about where the video is being taken.
No, nitwit. 1.07 seconds would be the time differential between the flight time of the bullet and the time of sound to reach the recording point.
Sound travels 1208 feet in 1.07 seconds.
If the sound went 1208 feet and arrived in 1.07 seconds, and the bullet arrived 1.07 seconds before the sound, the bullet took 0.00 seconds in flight time.
LOL. You're like a senile backseat driver who obsessively complains about (keeps pasting from) a wrong turn taken by a taxi driver 1.07 years ago while they were delivering you, on time (relatively speaking), to a compulsory (coincidental to the phase of the Moon) monthly appointment with your neurologist/psychotherapist.
Using Sound of Target Impact for Acoustic Reconstructions of Shooting Events
At page 2:
A microphone was placed a few centimeters from the muzzle to record both the muzzle blast and the sound of the bullet hitting the deer. The time recorded between the muzzle blast and bullet striking the target represents the sum of the bullet time of flight (tb) and the time for the sound to return to the microphone from the target (ts),
t = ts + tb = d/Vs + d/Vb
where d is the target distance, Vs is the velocity of sound, and Vb is the average bullet velocity over the distance.
At page 5:
These results show that it is possible to use an audio recording of a shooting event to accurately determine the distance between the target and the shooter. In cases where the location of the microphone is different, the mathematical details are different, but the ideas are the same.
At page 6:
A significant weakness in the study is the placement of the microphone near the muzzle of the gun, an unlikely location in most forensic cases....
Your recording is at a taxi nearly 400 feet away from the muzzle. You can do all the calculations you desire and the microphone will be no closer to the muzzle. The muzzle was likely around the corner, about 340 feet up, and some angular distance away from the microphone in the taxi. There was no direct path for the sound to reach the taxi.
The taxi did not pick up the sounds of the bullets striking people on the ground over 1200 feet away. The muzzle blast echoed back, but you do not know where from, or what path it took to the taxi at ground level.
A taxi recording indicates the muzzle blast with a delay by the time the sound took to reach the taxi, about .35 seconds at 400 feet. During that delay, the muzzle blast is on its way to some reflective surface which redirects the sound by some route to the taxi at ground level.
The elapsed time at the 400 foot distant taxi is not the elapsed time of the muzzle burst soundwave out and back. You ignored the ~0.35 second initial delay to reach the taxi, and you have no idea what reflective surface(s) redirected the sound before the echo arrived at the taxi.
You do have a nice picture with circles on it though.
The problem, of course, is related in your reference study.
Nope. I only referenced that study for the 2nd analysis - of audio/video recorded on the field. That analysis was done to refute the claim that a 2nd shooter, dressed as a policeman, was firing on the field. The observable difference between the bullet and report sound events succinctly refutes the asserted "proof" of a 2nd shooter on the field.
Regarding my initial meme "TEST FOR ECHO" -- Balistic data is NOT required to determine the total distance sound traveling from, and echoing back to, the ORIGIN point which is essentially where the Taxi driver was.
What would the Elapsed time between the Last Report sound event and the Last Bullet sound event be if, as the video alleged, the guy "dressed as police" was shooting?
Regarding my initial meme "TEST FOR ECHO" -- Balistic data is NOT required to determine the total distance sound traveling from, and echoing back to, the ORIGIN point which is essentially where the Taxi driver was.
The taxi was hardly at or near the origin point. It was 338+ feet away. The study placed a microphone "a few centimers" from the muzzle, not 10,302+ centimeters away.
The taxi was 338 feet down, some distance out from the building. Even if directly opposite the taxi, the muzzle had to travel 338+ feet to get to the taxi. That still take 0.299 seconds for the muzzle blast to reach the taxi from 338 feet.
Adjusting for your cited claim (at #118) that NYT reporting "suggests that Paddock was positioned directly above the camera at this point," with the taxi directly below the window, your blather has not materially changed the problem with your chartoon. The taxi microphone was not a few centimeters from the muzzle, it was over 338 feet away.
Yeah, you make believe that the sounds recorded in the taxi can yield an accurate measurement of distance.
The problem, of course, is related in your reference study.
Using Sound of Target Impact for Acoustic Reconstructions of Shooting Events
At page 2:
A microphone was placed a few centimeters from the muzzle to record both the muzzle blast and the sound of the bullet hitting the deer. The time recorded between the muzzle blast and bullet striking the target represents the sum of the bullet time of flight (tb) and the time for the sound to return to the microphone from the target (ts),
t = ts + tb = d/Vs + d/Vb
where d is the target distance, Vs is the velocity of sound, and Vb is the average bullet velocity over the distance.
At page 5:
These results show that it is possible to use an audio recording of a shooting event to accurately determine the distance between the target and the shooter. In cases where the location of the microphone is different, the mathematical details are different, but the ideas are the same.
At page 6:
A significant weakness in the study is the placement of the microphone near the muzzle of the gun, an unlikely location in most forensic cases....
Your recording is at a taxi over 338 feet away from the muzzle. You can do all the calculations you desire and the microphone will be no closer to the muzzle. The muzzle was likely around the corner, about 338 feet up, and some angular distance away from the microphone in the taxi.
The taxi did not pick up the sounds of the bullets striking people on the ground over 1200 feet away. The muzzle blast echoed back, but you do not know where from, or what path it took to the taxi at ground level.
A taxi recording indicates the muzzle blast with a delay by the time the sound took to reach the taxi, about .299 seconds at 338 feet. During that delay, the muzzle blast is on its way to some reflective surface which redirects the sound by some route to the taxi at ground level.
The elapsed time at the 338+ foot distant taxi is not the elapsed time of the muzzle burst soundwave out and back. You ignored the ~0.299 second initial delay to reach the taxi, and you have no idea what reflective surface(s) redirected the sound before the echo arrived at the taxi.
You do have a nice picture with circles on it though.
Also, as there was no firearm seen protruding from any window, if Paddock was the shooter, he and the firearm were inside the room. The sound of muzzle blast had to travel out through the hole in the window in a directional manner. No straight path to the taxi was available.
Which is irrelevant for the purpose of measuring the elapsed time between the initial Report sound event and the corresponding Echo event at the same location, at the bottom of the wall directly beneath the shooter.
Explain the difference between the Echos observed in Burst A and Burst B.
The shooter is in the same position. The taxi is in the same position. The "reflective surfaces" haven't moved. And the surface of the ground, along which the report shockwave radiated back from SOMEWHERE (probably closely relative to the aiming point), hasn't moved either.
[VxH #117] The ECHO observed and discussed in the "TEST FOR ECHO" meme is not the sound of bullet impact - it is the reflected report.
[nolu chan #121] The reportof what, reflected from what surface?
[VxH #123] Explain the difference between the Echos observed in Burst A and Burst B.
The question was,
The reportof what, reflected from what surface?
I am not interested in your evasive non-answering invitations to a snipe hunt.
If you do not know what the report was, or you do not know what it reflected from, say so. In such case, your times are meaningless for your chosen calculations.
Which is irrelevant for the purpose of measuring the elapsed time between the initial Report sound event and the corresponding Echo event at the same location
Which is irrelevant unless you had a microphone at the location of the muzzle blast, not 338+ feet away.
At ~.299s the sound reached the taxi. Also at .299s the sound had traveled 338 feet toward whatever reflective surface it found in the distance.
As the taxi is not at the location of the muzzle blast initiation, and your nonsense does not meet the conditions of the study which stipulated a microphone a few centimeters from the muzzle. The taxi was over 10,000 centimeters away.
What would the Elapsed time between the Last Report sound event and the Last Bullet sound event be....
It would be a positive number expression of time.
On your spreadsheet chartoon, notice that you calculate T = Tb - Ts.
You calculate elapsed time as the time it took the bullet to travel, minus the time it took the sound to travel.
The correct formula should be T = Ts Tb = d/Vs d/Vb.
As the bullet is supersonic, and sound is a constant, the sound would travel 400 yards in 1.06s and the bullet would travel in less than 1.06s. Subtracting 1.06 from a smaller number will always yield a negative number.
At 1200 feet, you calculate Tb as 0.448578s, and Ts as 1.062s and calculate the T as -0.6126, negative 0.6126 seconds. The average donkey could recognize that something is wrong when the result is negative time.
Just what do you think happens in negative 0.6126 seconds?
You could at least recognize that if you get a negative number, you have stated the required formula backwards, and you proceeded to perform the calculation backwards, and present the bass ackwards result of your misunderstanding of the study you looked at.
Moreover, while you state backwards that T = Tb - Ts, your spreadsheet never defines what T is supposed to represent. Negative 0.6126 is the time of what? What is the significance of this negative 0.6126 seconds (other than to demonstrate you did not understand the reference study)?
your spreadsheet never defines what T is supposed to represent.
T is the absolute value of the difference between Tb and Ts -- which corresponds to the elapsed time between T1 and T2 that is OBSERVED in the audio recording's amplitude graph.
It is that correspondence that is then used to find the range - which was generated from the ballistic data for intervals of 75 feet.
If the guy "dressed like police" was a shooter as alleged - the Elapsed Time between Bullet Impact sound events and Muzzle Report sound events would be much nearer to zero than what the audio shows.
I think everyone wants to grab the mantle of science for themselves and deride each other as kooks. Which may be mostly true.
OTOH, the official investigation is so miserably bad that you can't blame people for making up their own explanations when the FBI has botched it this badly.
The difference in time, 0.6126, is an ABSOLUTE value. Sign is irrelevant.
It is relevant when calculated and displayed on a spreadsheet. You explicitly calculated for and displayed the negative value. Had you calculated for an absolute value, a negative value would not appear. If your formula in the cell does not say it is an absolute value, you do not produce an absolute value.
You're not even reading from the relevant part of the paper - where the microphone adjacent to the victim scenario is discussed.
No, I read the correct part.
The formula is correct for a supersonic bullet only if the value is explicitly expressed as an absolute. Otherwise, the correct value is derived by changing the formula. Either will work. You did neither and derived negative times and published them that way.
Amicrophone was placed a few centimeters from the muzzleto record both the muzzle blast and the sound of the bullet hitting the deer. The time recorded between the muzzle blast and bullet striking the target represents the sum of the bullet time of flight (tb) and the time for the sound to return to the microphone from the target (ts), t = ts + tb = d/Vs + d/Vb
nolu chan
style: initial; text-decoration-color: initial"> posted on 2017-10-25 16:15:25 ET
And this is the correct section of the paper that deals with amicrophone AT THE TARGET, the scenario where the "shooter dressed as police" video in question was taken.
>>The formula is correct for a supersonic bullet only if the value is explicitly expressed as an absolute
The formula is fine just the way the authors of the paper wrote it. The negative time is perfectly acceptable IF you actually understand what the value and chart are saying:
The sound of the Report (Ts) event was recorded 0.6126 seconds after Tb and that time differential corresponds to a distance of 1200 ft from the shooter.
I think everyone wants to grab the mantle of science for themselves and deride each other as kooks. Which may be mostly true.
This is a good example of why Jefferson wanted WE common people educated. We're not supposed to be waiting for government "experts" to give us our opinions.
"... finally, that truth is great and will prevail if left to herself, that she is the proper and sufficient antagonist to error, and has nothing to fear from the conflict, unless by human interposition disarmed of her natural weapons, free argument and debate, errors ceasing to be dangerous when it is permitted freely to contradict them. "
"I HAVE SWORN UPON THE ALTAR OF GOD ETERNAL HOSTILITY TO EVERY FORM OF TYRANNY OVER THE MIND OF MAN" --Thomas Jefferson, 1786
I've always thought it likely that Jefferson's first objection to modern American government would be to the monument they built in his memory. He just wasn't that kind of guy.
I think that famous personalities in history could only speak to their own times. We like to imagine or pretend that they were some wise sages, imparting timeless wisdom for the ages, blah-blah-blah, insert three fingers and think deep thoughts, etc.
The truth is that the great men of history were creatures of their own times and only capable of speaking to the great issues of their times. And placing them on pedestals and trying to pretend that they were speaking to the issues of our time is just laziness or political hackery.
You might just as well start asking WWJT (What Would Jesus Tweet?). Well, obiously, Jesus wouldn't tweet anything and he wouldn't even imagine it. And if he could imagine it, he wouldn't bother to tweet.
I've always thought it likely that Jefferson's first objection to modern American government would be to the monument they built in his memory.
Have you ever been there?
It's not the man/statue that's being memorialized so much as the foundational American ideals for which there are trail-heads on each of the four walls.
TRUTH IS GREAT AND WILL PREVAIL.
People who don't understand Science will be bamboozled by those who do, or worse.
#140. To: Tooconservative, A K A Stone (#138)(Edited)
The difference in time between the Bullet sound event and the Muzzle Report sound event corresponds to a shooter distance of approximately 1350 feet away.
Is the guy dressed like a policeman 1350 feet away?
NO.
So the claim of the video subject of this thread, that "shooter dressed as police" - is DEBUNKED.
So the claim of the video subject of this thread, that "shooter dressed as police" - is DEBUNKED.
I never grasped why they thought there was any factual basis for this claim to begin with.
It just seemed like Kookbait to me, beginning to end. It was intended to appeal to the kooks and make some money for the con-men who created it when the kooks kept clicking on and reposting their kookery around the internet but especially on Fakebook and Twit-ter.
They have a need for their kookery. It is integral to their worldview, to their opinion of themselves and their denigrating opinions of others.
They start jonesing for a kookery within a few hours of any major tragedy. It happens over and over. 9/11, Newtown, Boston marathon, Vegas massacre, you name it. It is a very consistent pattern. It's a noxious kind of neurotic behavior.
Bring me . . . a Kookery!
And the wailing and gnashing of teeth if someone points out they are actual kooks ... oy vey.
A microphone was placed a few centimeters from the muzzle to record both the muzzle blast and the sound of the bullet hitting the deer. The time recorded between the muzzle blast and bullet striking the target represents the sum of the bullet time of flight (tb) and the time for the sound to return to the microphone from the target (ts), t = ts + tb = d/Vs + d/Vb
Regarding my initial meme "TEST FOR ECHO" -- Balistic data is NOT required to determine the total distance sound traveling from, and echoing back to, the ORIGIN point which is essentially where the Taxi driver was.
The taxi was hardly at or near the origin point. It was 338+ feet away. The study placed a microphone "a few centimers" from the muzzle, not 10,302+ centimeters away.
The taxi was 338 feet down, some distance out from the building. Even if directly opposite the taxi, the muzzle had to travel 338+ feet to get to the taxi. That still take 0.299 seconds for the muzzle blast to reach the taxi from 338 feet.
Adjusting for your cited claim (at #118) that NYT reporting "suggests that Paddock was positioned directly above the camera at this point," with the taxi directly below the window, your blather has not materially changed the problem with your chartoon. The taxi microphone was not a few centimeters from the muzzle, it was over 338 feet away.
Yeah, you make believe that the sounds recorded in the taxi can yield an accurate measurement of distance.
The problem, of course, is related in your reference study.
Using Sound of Target Impact for Acoustic Reconstructions of Shooting Events
At page 2:
A microphone was placed a few centimeters from the muzzle to record both the muzzle blast and the sound of the bullet hitting the deer. The time recorded between the muzzle blast and bullet striking the target represents the sum of the bullet time of flight (tb) and the time for the sound to return to the microphone from the target (ts),
t = ts + tb = d/Vs + d/Vb
where d is the target distance, Vs is the velocity of sound, and Vb is the average bullet velocity over the distance.
At page 5:
These results show that it is possible to use an audio recording of a shooting event to accurately determine the distance between the target and the shooter. In cases where the location of the microphone is different, the mathematical details are different, but the ideas are the same.
At page 6:
A significant weakness in the study is the placement of the microphone near the muzzle of the gun, an unlikely location in most forensic cases....
Your recording is at a taxi over 338 feet away from the muzzle. You can do all the calculations you desire and the microphone will be no closer to the muzzle. The muzzle was likely around the corner, about 338 feet up, and some angular distance away from the microphone in the taxi.
The taxi did not pick up the sounds of the bullets striking people on the ground over 1200 feet away. The muzzle blast echoed back, but you do not know where from, or what path it took to the taxi at ground level.
A taxi recording indicates the muzzle blast with a delay by the time the sound took to reach the taxi, about .299 seconds at 338 feet. During that delay, the muzzle blast is on its way to some reflective surface which redirects the sound by some route to the taxi at ground level.
The elapsed time at the 338+ foot distant taxi is not the elapsed time of the muzzle burst soundwave out and back. You ignored the ~0.299 second initial delay to reach the taxi, and you have no idea what reflective surface(s) redirected the sound before the echo arrived at the taxi.
You do have a nice picture with circles on it though.
Also, as there was no firearm seen protruding from any window, if Paddock was the shooter, he and the firearm were inside the room. The sound of muzzle blast had to travel out through the hole in the window in a directional manner. No straight path to the taxi was available.