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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