From: John Larkin
Subject: Re: Coming soon to a theatre near you - endless mischief potential
Date: Sat, 12 Oct 2002 09:05:45 -0700
Organization: Posted via Supernews, http://www.supernews.com
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On 12 Oct 2002 06:13:17 -0700, email@example.com (milne_v) wrote:
>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.
>1. Virtual Home Theater
>How about 3.1-speaker Dolby Digital sound? With hypersonic, you can
>eliminate the rear speakers in a 5.1 setup. Instead, you create
>virtual speakers on the back wall.
>2. Targeted Advertising
>"Get $1 off your next purchase of Wheaties," you might hear at the
>supermarket. Take a step to the right, and a different voice hawks
>3. Sound Bullets
>Jack the sound level up to 145 decibels, or 50 times the human
>threshold of pain, and an offshoot of hypersonic sound technology
>becomes a nonlethal weapon.
>4. Moving Movie voices
>For heightened realism, an array of directional speakers could follow
>actors as they walk across the silver screen, the sound shifting
>subtly as they turn their heads.
>5. Pointed Messages
>"You're out too far," a lifeguard could yell into his hypersonic
>megaphone, disturbing none of the bathing beauties nearby.
>6. Discreet Speakerphone
>With its adjustable reach, a hypersonic speakerphone wouldn't disturb
>your cube neighbors.
Total, silly nonsense. Air is not a nonlinear medium, at least at