From: email@example.com (Adam Seychell)
Subject: Re: Coming soon to a theatre near you - endless mischief potential
Date: 12 Oct 2002 15:31:53 -0700
NNTP-Posting-Date: 12 Oct 2002 22:31:53 GMT
I've heard these fictional claims before. Even if there were audiable
sounds due to secondary effects, I somehow don't think it will pass
the safety regulations around most of the world. Sorry, just a gut
feeling I have...
firstname.lastname@example.org (milne_v) wrote in message news:...
> We've heard hypersonic sound. It could change everything.
> by Suzanne Kantra Kirschner
> It's the most promising audio advance in years, and it's coming this
> fall: Hypersonic speakers, from American Technology (headed by the
> irrepressible Woody Norris, whose radical personal flying machine
> appeared on our August cover), focus sound in a tight beam, much like
> a laser focuses light. The technology was first demonstrated to
> Popular Science five years ago ("Best of What's New," Dec. '97), but
> high levels of distortion and low volume kept it in R&D labs. When it
> rolls out in Coke machines and other products over the next few
> months, audio quality will rival that of compact discs.
> The applications are many, from targeted advertising to virtual
> rear-channel speakers. The key is frequency: The ultrasonic speakers
> create sound at more than 20,000 cycles per second, a rate high enough
> to keep in a focused beam and beyond the range of human hearing. As
> the waves disperse, properties of the air cause them to break into
> three additional frequencies, one of which you can hear. This sonic
> frequency gets trapped within the other three, so it stays within the
> ultrasonic cone to create directional audio.
> Step into the beam and you hear the sound as if it were being
> generated inside your head. Reflect it off a surface and it sounds
> like it originated there. At 30,000 cycles, the sound can travel 150
> yards without any distortion or loss of volume. Here's a look at a few
> of the first applications.