Are infrasonic soundwaves dangerous? - AVS Forum
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post #1 of 37 Old 03-01-2011, 06:14 PM - Thread Starter
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It seems that there is a trend toward ever lower frequencies at ever higher SPL's in the forum, but I can't say that I've ever seen more than a quip in passing about their potential dangers.

This review paper attempts to summarize the research in the area. Infrasound: Brief Review of Toxicological Literature

http://ntp.niehs.nih.gov:8080/ntp/ht...Infrasound.pdf

The paper appears to be pretty well done and has some examples of infrasonic content and SPL, such as running, swimming, or standing in the wind.

My concern is that if the body is transparent to soundwaves, that means that our bodies compress and decompress at the molecular level as the pressure wave moves through. That just doesn't sound like the best thing to do...particularly to the brain. It reminds me of chonic traumatic encephalopathy, which is thought to be the cause of many conditions in athletes who receive countless (even low grade) blows to the head across their careers. The brain gets "torn apart" at the neuron level, until it appears to just disintegrate.

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post #2 of 37 Old 03-01-2011, 06:29 PM
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Experimental studies have been reported where humans or various species of animals (rats, mice, guinea pigs, chinchillas) have been exposed to infrasound in the laboratory.

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post #3 of 37 Old 03-01-2011, 06:31 PM
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While 140db is tremendously loud to our ear, which is built upon a very thin membrane that really is extrordinary at sound detection, the actual pressure level delta in room and the force that generates within our body is rather small compared to even modest physical blows.

While I wouldn't discount the possibility of chronic use causing detectable damage out of hand, I would think it is extremely unlikely.

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post #4 of 37 Old 03-01-2011, 06:45 PM
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Mythbusters subjected themselves to ridiculously loud/low sound levels with no real apparent effects, in search of the elusive brown note.

A quick google reveals: http://watchdocumentary.com/watch/my...57ec1ea72.html

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post #5 of 37 Old 03-01-2011, 06:58 PM
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Our bodies are mostly water. Did you ever try to compress water? Doesn't work too good

The minimal amount of pressure put out at even absurd levels shouldn't hurt you. The impact from walking down a flight of stairs puts more stress on your brain and body than subs ever will.
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post #6 of 37 Old 03-01-2011, 07:05 PM
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http://en.wikipedia.org/wiki/Sonic_weapon

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Demonstrated infrasonic weapon


The U.S. DOD has demonstrated phased arrays of infrasonic emitters. The weapon usually consists of a device that generates sound at about 7 Hz. The output from the device is routed (by pipes) to an array of open emitters. At this frequency, armor and concrete walls and other common building materials allow sound waves to pass through, providing little defense.[6] This presents logistic problems regarding operation of infrasonic weaponry without exposing operating personnel to the potentially damaging effects.
Physicist and researcher Jürgen Altmann, however, has suggested that infrasound "does not have the alleged drastic effects on humans" in his paper "Acoustic Weapons." While many sources make reference to military research into infrasonic weapons beginning with the work of Dr. Vladimir Gavreau, it is unclear as to whether or not these devices have potential use in conflict.

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post #7 of 37 Old 03-01-2011, 10:07 PM
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These people that live near wind farms in Australia seem to think that infrasonic sound waves are dangerous. Have a WATCH.
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post #8 of 37 Old 03-01-2011, 10:19 PM
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Anyone else raise an eyebrow to the claim that sound so low and powerful that it can pass with ease through armor and concrete walls is routed without issue by "pipes"?

Sort of like the bottle full of acid that can eat through any substance, no?

Again, while I won't say with absolution that bass doesn't cause damage beyond our hearing, it is exceedingly unlikely. This coming from both my engineering and physician backgrounds. The math and physiology just don't support these concerns.

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post #9 of 37 Old 03-02-2011, 02:10 AM
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"Again, while I won't say with absolution that bass doesn't cause damage beyond our hearing, it is exceedingly unlikely. This coming from both my engineering and physician backgrounds. The math and physiology just don't support these concerns. "


Agreed. The monetary cost to see if it would be damaging would be large. Anyone who rides a subway or a car with the windows open on a highway cn be subjected to large infrasonic spl on a daily basis.

JSS
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post #10 of 37 Old 03-02-2011, 03:01 AM
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At 3 in the morning subwoofer cat is very funny.

I still dont buy the notion the our bodies are completely transparent to LF. There has to be some amount of absortion by our skin when an LF pressure wave hits us. WAter doesnt compress, but it does move.

7 hz @ Xdb hitting the skin probably doesnt mean 7hz @ Xdb getting to our brain. What little that hasnt been absrobed or reflected to other parts cant be much more pressure than speaking a forceful "P" sound. Tapping your knuckles on the side of your head produces more effect felt by your brain.

Im sure that taken to an extreme...Sure 250db of 5hz will probably render you unconsious, but the maybe 140 that the best on this forum could muster at their couch? pppssshhh. I have had worse injuries from sneezing.
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post #11 of 37 Old 03-02-2011, 03:17 AM
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Tesla invented sound wave technology that was no bigger than a shoe box and if he sit that box on "whatever" he could bring down buildings. Of course at the time of his death our gov't went through his papers but they said they returned and gave all his notes to the Tesla museum where he was born...I believe he either had einstein or edison stand on or hold one of those units and it made him shake and Tesla said do not hold it too long and he lost control of his body fluid. Tesla also said he could split the earth in half with that same technology.

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post #12 of 37 Old 03-02-2011, 03:22 AM
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Quote:
Originally Posted by Browninggold View Post
Tesla invented sound wave technology that was no bigger than a shoe box and if he sit that box on "whatever" he could bring down buildings. Of course at the time of his death our gov't went through his papers but they said they returned and gave all his notes to the Tesla museum where he was born...I believe he either had einstein or edison stand on or hold one of those units and it made him shake and Tesla said do not hold it too long and he lost control of his body fluid. Tesla also said he could split the earth in half with that same technology.
IIRC that wasnt a sound wave device, it was a device with an actual weight on it that oscillated.
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post #13 of 37 Old 03-02-2011, 03:36 AM
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Quote:
Originally Posted by Starkiller4299 View Post
Mythbusters subjected themselves to ridiculously loud/low sound levels with no real apparent effects
Yeah, but they're already wacked out
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post #14 of 37 Old 03-02-2011, 07:39 AM
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Quote:
Originally Posted by MoFinWiley View Post

Im sure that taken to an extreme...Sure 250db of 5hz will probably render you unconsious, but the maybe 140 that the best on this forum could muster at their couch? pppssshhh. I have had worse injuries from sneezing.

Infrasonic waves can be lethal. What do you think a shock wave from an explosion is? An infrasonic wave with massive decibelage. (I love making up new words!)

The loudest sound theoretically possible at normal atmospheric pressure is 194.094db, according to Wikipedia.

When Kakatoa erupted in 1883, the sound was reported to have cracked concrete walls 100 miles away, and was loud enough to be heard 3000 miles away! Some people have estimated the pressure wave to be over 300db. I think the reason it can be over the 194db limit is because 194db assumes a full wave with the trough at 0 pressure. An explosive sound wave is more of a giant peak db wave.

So if you really want some hard core bass, fill your sonotubes with TNT. Only problem is, you'll only get to hear it once...

Edit: Found some info on audio lethality. A 165db pressure wave is likely to generate shrapnel. A 180db pressure wave will throw you 10fps. A pressure wave of 198-202db is what is required to suffer death by sound.

http://www.makeitlouder.com/Decibel%20Level%20Chart.txt
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post #15 of 37 Old 03-02-2011, 08:13 AM
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Infrasonic could be very dangerous if it p***es off a herd of nearby elephants.

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post #16 of 37 Old 03-02-2011, 08:14 AM
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In other words, anything you generate in your residential HT won't do anything to you other than damage your hearing.

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post #17 of 37 Old 03-02-2011, 11:44 AM
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Quote:
Originally Posted by MoFinWiley View Post
IIRC that wasnt a sound wave device, it was a device with an actual weight on it that oscillated.
Indeed. The principal was that if you couple with the resonant frequency of whatever you put it on (bridge, building, etc) the energy you put in would just keep building and building. Very crazy stuff that can indeed take down bridges and stuff.
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post #18 of 37 Old 03-02-2011, 01:00 PM
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Quote:
Originally Posted by notnyt View Post

Indeed. The principal was that if you couple with the resonant frequency of whatever you put it on (bridge, building, etc) the energy you put in would just keep building and building. Very crazy stuff that can indeed take down bridges and stuff.

Did anyone else see the Mythbusters where they tested this? I don't remember it very well but I believe the conclusion was that bringing down a building/bridge was an exaggeration
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post #19 of 37 Old 03-02-2011, 01:42 PM
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Two points:
1 Mythbusters = idiots (IMHO).
2 Tacoma Narrows.

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post #20 of 37 Old 03-02-2011, 02:40 PM
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Love the subwoofer cat

Quote:
Originally Posted by petew View Post

Two points:

2 Tacoma Narrows.

Had nothing to do with sound, although I guess you could say that the wind-driven mechanical resonance of the bridge structure was high level pulsating DC sound.

Noah
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post #21 of 37 Old 03-02-2011, 02:48 PM
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Quote:
Originally Posted by petew View Post

2 Tacoma Narrows.

Quote:
Originally Posted by noah katz View Post

Had nothing to do with sound, although I guess you could say that the wind-driven mechanical resonance of the bridge structure was high level pulsating DC sound.

Yup, I believe that's a different phenomenon altogether:
http://en.wikipedia.org/wiki/Aeroelasticity#Flutter
http://en.wikipedia.org/wiki/Tacoma_Narrows_Bridge
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post #22 of 37 Old 03-02-2011, 03:47 PM
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Quote:
Originally Posted by lennon_68 View Post

Did anyone else see the Mythbusters where they tested this? I don't remember it very well but I believe the conclusion was that bringing down a building/bridge was an exaggeration

I saw that. It was pretty obvious from the beginning that it wasn't going to bring the bridge down, but they could measure the oscillation a good distance away nevertheless.

Mythbusters need one physicist on their staff. Sometimes they go to great length to prove to themselves that something works when a simple equation would have done the same. Equation aren't as good for TV though.

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post #23 of 37 Old 03-02-2011, 04:28 PM
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Quote:
Originally Posted by noah katz View Post

Had nothing to do with sound...

Neither did tesla's device.

Though I have to say, even though tesla was a genious some people get a little carried away with the claims of what he achieved. It stops at no less than zero point energy powered gravitational drives that skirt relativistic speed limits.

As far as bringing down buildings and bridges, certainly possible but any building of sufficient height to care about toppling has enough internal damping in the structure to laugh at the amount of energy transfer from a shoebox sized device.

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post #24 of 37 Old 03-03-2011, 07:37 PM
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Don't the large whales communicate with very low frequency sounds? The sounds are supposed to go long distances. I wonder what other effects within the ocean happen when the whales talk?
Also, don't or didn't submarine communications rely on vlf antenna and signals?

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post #25 of 37 Old 03-03-2011, 09:28 PM
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I have been running a 14Hz sine wave, my tuning, for the last 1/2 hour at a moderate level with my GF sleeping on the bleechers in front of them and her son in the other BR. Neither seems to be affected. I, on the other hand, oh wait... I've always been this way.
Amps are a touch warm, not at all close to hot, same as the drivers. I can hear things rattling throughout the house. When the heater kicks in, the HVAC quiets down a bit, when it shuts off, the vents rattle more.
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post #26 of 37 Old 03-03-2011, 09:56 PM
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decided to try a lil experiment. My GF and her son are sleeping so I put on a 14Hz sine wave at a moderate level. Not loud enough to disturb them or over heat the amps or subs, but enough to rattle things throughout the house. I can feel the floor wobble, subs moving about 1/6th of an inch, little bit of air puffing through the ports.

http://www.youtube.com/watch?v=fr0q21fAnSk
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post #27 of 37 Old 03-04-2011, 04:52 AM
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Quote:
Originally Posted by kryptonitewhite View Post

decided to try a lil experiment. My GF and her son are sleeping so I put on a 14Hz sine wave at a moderate level. Not loud enough to disturb them or over heat the amps or subs, but enough to rattle things throughout the house. I can feel the floor wobble, subs moving about 1/6th of an inch, little bit of air puffing through the ports.

You monster! Do you work for Vault-Tec? Are you implanting subconscious suggestions through the use of ELF white noise?

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post #28 of 37 Old 03-04-2011, 08:06 PM
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Quote:
Originally Posted by Starkiller4299 View Post

Mythbusters subjected themselves to ridiculously loud/low sound levels with no real apparent effects, in search of the elusive brown note.

A quick google reveals: http://watchdocumentary.com/watch/my...57ec1ea72.html


I've posted this on the Mythbusters forum before.

I believe they should retest this. They were talking about how loud it was at low frequencies, but I seriously don't believe they tested this as well as they should have. Just watching that again they did 108 db at 5 hz and i believe 114 at 9 hz. There are guys on here that can do that in their rooms. This is where I believe they should do their testing at. They were doing their testing outdoors and had gaps between the enclosures which was more than enough for sound to leak out. I'm not sure if the brown note is something that can actually happen, but I think they owe it to us audio freaks to test this again, indoors or in a car, with 130 db and higher range at 5-12 hz. This can be done. Plus the fact that something was wrong with their testing I do believe. Ricci managed short term of 108 db with a xxx 18" llt at 2 meters. That's one driver. I'm not saying those levels will work and actually create the "brown" but i believe it should be tested again.

Kryptonite...what kind of spl do you get with your fart boxes at those low frequencies? I'm guessing you get well over 120.
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post #29 of 37 Old 03-04-2011, 08:15 PM
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Quote:
Originally Posted by brandonnash View Post

Kryptonite...what kind of spl do you get with your fart boxes at those low frequencies? I'm guessing you get well over 120.

He doesn't have a meter
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post #30 of 37 Old 03-04-2011, 08:34 PM
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Nah, I am not buying it.
I am guessing that if you had prolonged exposure at very high SPL levels you may get some nausea or discomfort, headaches, etc.

But, I would guess depending on where you live, etc. you are exposed to more than you think. I think it would take extreme levels to do any real harm.

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