So...

sound in air consists of alternating raised pressure and lowered pressure areas traveling through the air at, hey! the speed of sound.

We consider atmospheric pressure to be about 14.7 psi.

When sound occurs, the variations in pressure take the absolute pressure up and down around this 14.7 psi value.

At what sound level do the areas of lowered pressure reach 0 psi, meaning a complete vacuum? It would be impossible for that portion of the wave to be any louder, meaning that sound above that level would be distorted as though, electrically, run through a rectifier.

Just wondering.

I understand that the major amount of damage from near Mt. St. Helens was caused by the "sound" of the explosion being so intense that an actual wave of liquefied (due to pressure) air flew away in all directions from the center. The trees didn't yield to a wind; they were mowed down by a liquid air tsunami.

Found this unit conversion a couple places, so I assume it's the accepted value.  That's freakin loud.....   Ernie, what made you think of this?



www.silcom.com/~aludwig/Physics/UNITS&.html

1 atmosphere = 1.0332x104 kg-m-2 = 2116.2 lbs.-ft2 = 14.7 psi = 76 cm Hg
= 1.0132x105 Pa = 197.1 dB SPL (Swing from total vacuum to 2-atm)

 Some guy died from reproducing frequencies in his studio that are suppose to cause hulucinations and ended up "liquifying his organs", according to the tv show, "1000 ways to die"

Where do you read this? Nuclear blasts produce overpressures of less than 50 psi. Hardly enough to liquefy air. However an overpressure of 50 psi will travel at 934 mph. That will tear some sh!t up.

Since I want sources...

here

here

and here

[Link: remotecentral.com]

That's pretty funny, since davidcasemore quoted your post in that thread. HE saw the connection even though I didn't mention it. Jumper, kids' party, loudest possible noise before half of the waveform would try to be less pressure than a vacuum... it all fits together to me!

I'll bet I made it up in my fertile mind, just sitting here, thinking, one day.

I've always found it odd that 1atm=14.7psi and for perfect combustion in an automobile engine you need an air-to-fuel ratio of 14.7, stoichiometric mixture.

Now don't forget that the 14.7 psi is at sea level at a certain temperature and with no humidity, like that ever happens.

As for the Mt St Helens "air tsunami", from what I remember the lateral blast was traveling over 200mph but it included ash and debris. That is what knocked things down, up to I think 20 miles. If I remember right the majority of people that died did so from suffocation. I'll have to look later when I get to my computer to see if I can find a picture that showed the trees on the backside of the mountain were standing tall, as if nothing happened. The blast side was flattened in a fan shape.

Reading threads like this make me wonder if i smoked too much marijuana as a kid... or not enough.

 I just created my list of people to avoid at the bar during CEDIA.  I thank you, and my sanity thanks you. :)

+1

Did you mean 39Cent Stamp, or me?

I have been on the list for a couple of years now.

This is called a pyroclastic flow. The overpressure (shock wave) was first but only got stuff fairly close. The pyroclastic flow reached 19 miles out and nearly reached the speed of sound. (citation) The temperature of the gas was as high as 680 degrees Fahrenheit. So while you technically die of asphyxiation it would burn a lot to.

pryoclastic flow

While I won't be at CEDIA I can talk about things other than science. :-)

If a tree falls in the forest and nobody is there... does it make a sound?

More to the point, if Mr. Stanley drills a hole and shuts down a high-rise building and an entire city block, but we don't hear about it, do we laugh anyway?