New Alienentity video on WTC 7

leftysergeant said:
But a noise originating inside the canyon walls will stay inside and travel some distance. Note that we can clearly hear the much softer sounds of the breakup of WTC 7 much more clearly as more of the action occurs at street level, well into collapse.

So, basicly, Java Man, you have nothing of forensic value here.
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Yes noise will stay in the canyon walls, but:

- there are many "canyon walls" in downtown NY, each taking sound away from the camera and only one bringing it to the camera
- you will not get a distinct sound signature from the blast because there are building standing in between
- you will get a distorted sound signature that is a sum of the sound waves echoing along the canyon wall leading to you

Some noise will be colinear to the street, but most of it will not. It will bounce of one wall and then the other and the other. Some will hit the walls at lower angles and some at higher angles. Those at lower angles will reach you sooner and those at higher angles will take longer (as they bounce more times to reach you and their path is longer). Thus spreading the "bang"(and energy) over a longer period of time.

There is also the fact that (unlike stealth aircraft) buildings are large squared boxes laid out over perpendicular lines called streets. Just like you show us with your car example the sound will bounce right back to the source, the collapsing building. Without oblique surfaces like a stealth aircraft to divert the energy it will mostly happen as you say, bounce right back to the source.

In other words why would sound that is comfortably traveling down a "street canyon" all of the sudden make a left or right turn and come headed your way?
 
Java Man said:
Yes noise will stay in the canyon walls, but:

- there are many "canyon walls" in downtown NY, each taking sound away from the camera and only one bringing it to the camera
- you will not get a distinct sound signature from the blast because there are building standing in between
- you will get a distorted sound signature that is a sum of the sound waves echoing along the canyon wall leading to you

Some noise will be colinear to the street, but most of it will not. It will bounce of one wall and then the other and the other. Some will hit the walls at lower angles and some at higher angles. Those at lower angles will reach you sooner and those at higher angles will take longer (as they bounce more times to reach you and their path is longer). Thus spreading the "bang"(and energy) over a longer period of time.

There is also the fact that (unlike stealth aircraft) buildings are large squared boxes laid out over perpendicular lines called streets. Just like you show us with your car example the sound will bounce right back to the source, the collapsing building. Without oblique surfaces like a stealth aircraft to divert the energy it will mostly happen as you say, bounce right back to the source.

In other words why would sound that is comfortably traveling down a "street canyon" all of the sudden make a left or right turn and come headed your way?
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There are plenty of youtube videos of explosive demolitions in large cities whose "canyons" would have properties as you describe.
Some of these taken from many blocks away.

Invariably, all of these videos feature many very clearly audible BANGs. Most of the time, these BANGs are INSANELY loud, awesomely loud, often shocking even the people who fully expected them.

Never are these BANGs missing or uncertain.
 
Java Man said:
Well if sound were to so easily reverberate in NY wouldn't it make any noise unbearable? That effect would apply for everyday, not just 911. Right?

I think you're just grabbing on to a phenomenon that does happen and applying it here to justify your cause without really thinking about the implications.
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Java Man said:
Yes noise will stay in the canyon walls, but:

- there are many "canyon walls" in downtown NY, each taking sound away from the camera and only one bringing it to the camera
- you will not get a distinct sound signature from the blast because there are building standing in between
- you will get a distorted sound signature that is a sum of the sound waves echoing along the canyon wall leading to you
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I hope this doesn't sound condescending, but have you ever been to a large city?

I recommend that you visit NYC during Fleet Week, or Chicago during the Air and Water Show. You will experience all of these phenomena in a way that you won't need it explained.

Specific to explosions, visit any big city high rise district during a nearby fireworks display. Trust me when I tell you that you hear distinct, "boom boom boom" explosions, even in the heart of a big city high rise canyon district. And the directionality of the microphones in the videos referenced here would have picked up a controlled demolition-type blast very, very clearly. Especially the Ashley Banfield one.
 
Java Man said:
Oh so why do people build these between highways and residential areas?

[qimg]http://designshrine.net/wp-content/plugins/wp-o-matic/cache/aee31_AE002a.jpg[/qimg]
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To attenuate the 60dB or what noise levels (at half a mile) that come from rubber tires roling on asphalt, and some already attenuated motors sputtering.

If you explode the 8-10 pounds worth of TNT on the same highway, everybody in the residential area would hear the INSANELY LOUD BANG.

If these barriers can reduce noise by, say, 30dB (a very very tall order, quite unrealistic, really), then the 60dB of noisy highway (equivalent to TV set 3 feet away) would go down to bearly audible 30dB (calm room). The 130dB of that explosion at half a mile away would go down to 100dB - equivalent to a jack-hammer 3 feet away.
 
Oystein said:
If these barriers can reduce noise by, say, 30dB (a very very tall order, quite unrealistic, really), then the 60dB of noisy highway (equivalent to TV set 3 feet away) would go down to bearly audible 30dB (calm room). The 130dB of that explosion at half a mile away would go down to 100dB - equivalent to a jack-hammer 3 feet away.
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You're not taking into consideration the dampening of being "half a mile away"
 
carlitos said:
Trust me when I tell you that you hear distinct, "boom boom boom" explosions, even in the heart of a big city high rise canyon district.
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Yes, but that's not the issue here. The question is do you hear the boom booms less loud that without the interfering canyons. The issue here is that the debunker implies that the canyons would act as "amplifiers". Basically stating that his point stands because the canyons would canalize the sound and make it sound louder than a straight line of sight to the blast. Which is very hard to believe just like that. Sounds like he's just pulling arguments off the top of his head to support his statement.
 
Java Man said:
You're not taking into consideration the dampening of being "half a mile away"
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What "damping"? You seem to have a problem with your acoustics terminology and concepts.

Have you ever been within a few feet of the firing of a rifle?

Yes or no (no is ok)

If yes, how far?
 
BigAl said:
What "damping"? You seem to have a problem with your acoustics terminology and concepts.

Have you ever been within a few feet of the firing of a rifle?

Yes or no (no is ok)

If yes, how far?
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Yes, 9mm and 45 autos, M1 rifle and 12 gauge shotgun. Distance: arm's length or less.
 
Java Man said:
Yes, but that's not the issue here. The question is do you hear the boom booms less loud that without the interfering canyons. .
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Demolitions are so loud that to the extent you have any valid points about acoustics in general, they are irrelevant to what the many thousands of people near WTC didn't hear on 9/11.
 
BigAl said:
Have you ever been within a few feet of the firing of a rifle?

Yes or no (no is ok)

If yes, how far?
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I'm still waiting for the relevance of the rifle fire. Was it meant to have any value to the discussion at hand or just portray me as some soft cored liberal?
 
Java Man said:
Yes, 9mm and 45 autos, M1 rifle and 12 gauge shotgun. Distance: arm's length or less.
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Great. The smallest explosive charge capable of cutting a WTC7 beam (*) generates a 130db blast and at half a mile would be comparable to being a few yards from the discharge of your M1.

On 9/11 there were many many thousands of people within that radius and many much closer.Nobody heard anything contestant with man-made demolition


* Video: Why the Building (WTC7) Fell (3:40 minutes)
http://www.youtube.com/watch?v=PK_iBYSqEsc​

QA http://www.nist.gov/public_affairs/factsheet/wtc_qa_082108.cfm
 
BigAl said:
Damping is real but doesn't apply in a world of concrete.
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Really?

http://www.amazon.com/reader/047108...3189&query=damping concrete#reader_0471081221

http://www.amazon.com/retrofit-exis...=sr_1_3?s=books&ie=UTF8&qid=1283873189&sr=1-3

Publisher: US Army Corps of Engineers, Construction Engineering Research Laboratories National Technical Information Service, distributor (1995)

http://www.amazon.com/Damping-low-a...=sr_1_1?s=books&ie=UTF8&qid=1283873189&sr=1-1

Publisher: Division of Engineering, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission (1993)
 
Java Man said:
You're not taking into consideration the dampening of being "half a mile away"
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Wrong. I did. I wrote "half a mile away" next to two dB numbers. And meant it. I wrote "at 3 feet (away)" next to two other dB numbers. And meant it, too. Try reading my post a second time.
 
Java Man said:
Yes, but that's not the issue here. The question is do you hear the boom booms less loud that without the interfering canyons.
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...and the answer to your highlighted question, for the Salomon Brothers Building, on 9/11/2001, in real life and in all of these videos, most notably the Ashley Banfield one, is "yes." The booms would be so loud, and the acoustics of the area, would result in thousands of ear-witnesses and all the videos' capturing the sound.

There were no explosives anywhere near that building on that day, and they did not explode. Were you trying to make some other point than this, or are you just arguing for the sake of arguing?
 
Oystein said:
Wrong. I did. I wrote "half a mile away" next to two dB numbers. And meant it. I wrote "at 3 feet (away)" next to two other dB numbers. And meant it, too. Try reading my post a second time.
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It seems to be contradictory to BigAl's statement.
 
arguing for the sake of arguing

Java Man said:
Really?

http://www.amazon.com/reader/047108...3189&query=damping concrete#reader_0471081221

http://www.amazon.com/retrofit-exis...=sr_1_3?s=books&ie=UTF8&qid=1283873189&sr=1-3

Publisher: US Army Corps of Engineers, Construction Engineering Research Laboratories National Technical Information Service, distributor (1995)

http://www.amazon.com/Damping-low-a...=sr_1_1?s=books&ie=UTF8&qid=1283873189&sr=1-1

Publisher: Division of Engineering, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission (1993)
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Given that you replied one minute after BigAl's post, had you previously read and understood the material at the links above?
 
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