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[Ned Ward]

Was listening to this tonight on the radio driving to pick up my daughter from basketball practice, but after googling I just realized this was a bit from over 3 years ago, which may or may not be why Tom Danley wasn't interviewed (although he should have been).


http://www.radiolab.org/story/96854-walls-jericho/


Guessing a few Jericho boxes and a Matterhorn would have made short work of a mud wall...

[Ivan Beaver]

Was listening to this tonight on the radio driving to pick up my daughter from basketball practice, but after googling I just realized this was a bit from over 3 years ago, which may or may not be why Tom Danley wasn't interviewed (although he should have been).


http://www.radiolab.org/story/96854-walls-jericho/


Guessing a few Jericho boxes and a Matterhorn would have made short work of a mud wall...

Of course the key to breaking something with sound is to find the resonant freq.  Just like with a wine glass.  It is not so much the SPL (which you have to have) but if it is not at the resonant freq-noting will happen.

Just like the brown note theory.  Until you find the right freq for a particular person-nothing is going to happen.

Of course other things might happen-such as other organs getting ruptured, permanent damage to some body parts-maybe heart and such.

It is for that reason that we have not used the Matterhorn to try to reproduce the "brown note".  Simply to much liability. 

While it would be funny and great to get somebody to crap their pants (and everybody around as well probably), the possibility of serious bodily damage is also high.

We don't want to be the ones to find out.

[John Roberts {JR}]

Of course the key to breaking something with sound is to find the resonant freq.  Just like with a wine glass.  It is not so much the SPL (which you have to have) but if it is not at the resonant freq-noting will happen.

Just like the brown note theory.  Until you find the right freq for a particular person-nothing is going to happen.

Of course other things might happen-such as other organs getting ruptured, permanent damage to some body parts-maybe heart and such.

It is for that reason that we have not used the Matterhorn to try to reproduce the "brown note".  Simply to much liability. 

While it would be funny and great to get somebody to crap their pants (and everybody around as well probably), the possibility of serious bodily damage is also high.

We don't want to be the ones to find out.

That sounds like good judgement. I suspect there may be some resonances related to sundry body masses and suspension compliances, but unlike pipe hammer in water pipes, I suspect the soft walls of our internal plumbing would be inclined to flex with the internal media, perhaps leading to internal catastrophic failure before sphincter release.

That said I recall many years ago having a conversation with Rudy Bozak (RIP) about extended very LF response and he related to me that the brown note myth was not a myth. I doubt he was pulling my leg, and I did not press him for details. My speculation is that it may have actually happened once to some unfortunate individual, and that story became legend. It does not strike me as a reliable or safe phenomenon.



JR     

[John Halliburton]

That sounds like good judgement. I suspect there may be some resonances related to sundry body masses and suspension compliances, but unlike pipe hammer in water pipes, I suspect the soft walls of our internal plumbing would be inclined to flex with the internal media, perhaps leading to internal catastrophic failure before sphincter release.

That said I recall many years ago having a conversation with Rudy Bozak (RIP) about extended very LF response and he related to me that the brown note myth was not a myth. I doubt he was pulling my leg, and I did not press him for details. My speculation is that it may have actually happened once to some unfortunate individual, and that story became legend. It does not strike me as a reliable or safe phenomenon.



JR   

Having(along with Tom and other old Intersonics personnel) been exposed to some very interesting acoustic output over the years, in this case the sonic boom simulator he designed and we built for Georgia Tech, I'm not convinced there is a "brown note". 

I'd like to mention that observations of others during these projects showed no lines formed at the facilities by all those involved or nearby.

The sonic boom simulator was capable of reproduction down to 3hz.  I believe the threshold of actually hearing that is 120db.  There was a lot of energy coming off that device.

Best regards,

John

[Ivan Beaver]

That said I recall many years ago having a conversation with Rudy Bozak (RIP) about extended very LF response and he related to me that the brown note myth was not a myth. I doubt he was pulling my leg, and I did not press him for details. My speculation is that it may have actually happened once to some unfortunate individual, and that story became legend. It does not strike me as a reliable or safe phenomenon.



JR   

Let's say for example that it did happen to somebody.  Was it the actual freq/level that did it-or was it because that person was so "amazed" or needed to go anyway-------------

I know of a case that a female fan was allowed to touch the tour bus of her favorite country singer that she peed all over herself because she was so happy.

Maybe the same sort of thing.  Just sayin'

I will say for fact-that even at moderate to low levels-low freq energy can make you feel a bit "weird" and some people very uncomfortable.  We do it all the time-so much higher levels could be a real problem.

The interesting thing is that every time we let somebody listen to the Matterhorn, in the offices it is QUITE a bit more interesting than those outside the actual loudspeaker.

It seems as if the level is at least 10-20dB louder and all sorts of things start rattling/shaking etc.  Yet you don't actually hear anything-but you do "sense" it.

When you stand outside the cabinet-it sure doesn't seem as if it that loud or that sort of thing would be happening.

[Jack Arnott]

Of course the key to breaking something with sound is to find the resonant freq.  Just like with a wine glass.  It is not so much the SPL (which you have to have) but if it is not at the resonant freq-noting will happen.

This is what I was thinking when listening.
I was also remembering the stories of Tesla, and his little attachments that created vibrations.
Small at first, but they steadily grew and compounded, till the buildings were shaking, and people running out of them.
From what I recall he would then detach the device, and the waves would subside. 

[John Roberts {JR}]

This is what I was thinking when listening.
I was also remembering the stories of Tesla, and his little attachments that created vibrations.
Small at first, but they steadily grew and compounded, till the buildings were shaking, and people running out of them.
From what I recall he would then detach the device, and the waves would subside.

Yup, the Tesla device was like pushing a child on a swing such that you added a little more energy than was lost each time the child swings by. Over time the child will swing way too high.

For a very massive structure, the natural frequency of resonance will be quite low, and compliance allowing that mass to move freely will generally not be very flexible. It probably took some skill and experimentation to find a suitable anti-node (region of high amplitude) to apply the repetitive force. Applying it to a node would have no result. Like trying to pluck a guitar string at it's endpoints.  Any significant amplitude of simple harmonic motion of massive objects could easily break stuff. I'm  glad I didn't live near him. 

JR   

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