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Re: Woody Norris HyperSonic Sound speaker article

Subject: Re: Woody Norris HyperSonic Sound speaker article
From: Wild Sanctuary <>
Date: Tue, 25 Mar 2003 16:46:52 -0800
Indeed, we do, Adam. We're the reps for the emitter (HSS) for public 
space installations. I demonstrated it at the last Nat. Sounds 
Society last year at the Sierra workshop and have one here for demo.

It works by utilizing the instantaneous sum/difference signals of two 
ultrasound frequencies, tossing the sum and using the difference 
signal as a carrier for anything within the human range of hearing. 
Using an array of tiny transducers, it focusses the signal such that 
it is almost laser-like, meaning that the beam is very narrow. If one 
is even slightly outside the beam, the signal cannot be heard.  It is 
also quite un-intuitive in that the signal carries over extremely 
long distances without attenuation (as happens with normal speakers 
and the inverse square law). There are some problems with the package 
as it currently is presented, the most obvious one being the narrow 
range of the signal (abt. 500Hz to about 9kHz). It cannot focus low 
frequency for obvious reasons, but the company is constantly 
improving the hi-freq response with each successive iteration.

Bernie Krause

Wild Sanctuary, Inc.
P. O. Box 536
Glen Ellen, CA 95442
707-996-6677 tel
707-996-0280 fax
http://www.wildsanctuary.com

>This is a very interesting article in the NY Times on an invention
>by Woody Norris "...called HyperSonic Sound (HSS). The aluminum
>plate is connected to a CD player and an odd amplifier -- actually,
>a very odd and very new amplifier -- that directs sound much as a
>laser beam directs light."
>
>Sounds like an interesting concept. I wonder what a bird would think
>about this used for field playback? Or using it for localized sound
>playback in a museum exhibit. (I'd think that there would be some
>dispersion inside a room once it hit surfaces, even if the sound
>eminated in a beam).
>
>Anyone know more, or if this actually works?
>
>Article is at:
>http://www.nytimes.com/2003/03/23/magazine/23SOUND.html
>
>- Adam Liberman
>Liberman Sound
>
>
>
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