acoustic interferometry!

Jim Shaffer, Jr. ( (no email) )
Tue, 7 Apr 1998 17:13:49 -0400

> From: Bob Paddock <>
>"Sound sans Speakers"
> Forget those boxy speakers. The next sound you hear
>may come from a disc the size of an Oreo cookie.
> Each disc -- you'll need two for stereo sound -- is
>covered with small, circular crystals that produce
>what inventor Elwood G. Norris call HyperSonic Sound
>(HSS). Existing speaker systems use electrical signals
>to vibrate a thin diaphragm and produce sound within
>an audible range; Norris' crystals pulsate thousands
>of times faster and generate a pair of ultrasonic
>waves (one constant and one variable) at frequencies
>beyond human nearing. The interaction of the two waves
>produces a third wave that can be heard. By
>manipulating the variable wave against the constant or
>reference wave, a variety of tones can be produced
>using very little power, generally less than 50 watts.
>The crystals themselves cost little to make.
> HSS also creates a startling special effect: Sound
>can be projected to a certain spot, much the way that
>light is projected onto a surface with a flashlight.
>Instead of sound filling a room, it is directed
>straight at the listener, almost as if it were being
>created in mid-air. The advantage is that the
>distortion that's created as the sound bounces off
>walls and other objects -- those echoes that arrive
>at your ear a little "late" -- is eliminated, thus
>enabling HSS to deliver the fidelity promised by
>digital compact discs.
> Norris' American Technology Corp. is now
>licensing HSS to several companies. Among the first
>is Carver Corp., the well-known audio manufacturer,
>which expects to use HSS in a new product slated
>for next fall. HSS may be the biggest breakthrough
>since speakers were invented in 1925. - F.V.
>I've uncovered the following URL's for those who wish
>to explore further:
>I'd escpecially recommend the whitepaper.
-- "Any tapes left in a car for longer than about a fortnight automaticallymetamorphose into 'Best Of Queen' albums." --Neil Gaiman & Terry Pratchett, "Good Omens"