slightly scary but nevertheless interesting technology #1 of 2

[Richard LaFortune]

Woody Norris has a way of getting inside your head ...

by David Sparrow




 Woody Norris has a way of getting inside your head.
No, we don't mean his overpowering handshake or
Barnumesque penchant for self-promotion ("This is the
biggest thing in audio in 77 years"). We mean
HyperSonic Sound, his latest creation. (A prolific
inventor, Norris, 64, also won a Best of What's New
for a personal flying machine.)

Unlike traditional speakers, which scatter sound,
Norris' device streams it in a precise, laser-like
beam for up to 150 yards with almost no degradation in
quality or volume. If that seems incredible, trust me,
it is.

When I met Norris in September he pointed the
7-inch-square emitter at me from 30 feet away.
Suddenly I heard the sound of birds chirping. The
noise didn't seem to emanate from his device; I felt
like it was generated inside my noggin. Yet a guy just
2 feet away from me couldn't hear it.

How does it work? The piezoelectric transducer emits
sound at frequencies above the human ear's
20,000-cycle threshold. Unlike low-frequency waves,
the high-frequency signals don't spread out as they
travel through air. Yet they do interact with the air
to induce a related set of ultrasonic waves. These
waves combine with the original waves, interfering to
create an audible signal, focused into a beam.

The applications are numerous, if not apparent:
Thousands of soda machines in Tokyo will soon bombard
passersby with the enticing sound of a Coke being
poured, and several U.S. supermarkets will promote
products to shoppers as they walk down corresponding
aisles. Eventually HyperSonic Sound might enable a
nightclub to play disco on one side of the dance floor
and salsa on the other. Ambulances equipped with
hypersonic sirens could clear the streets without
waking the neighbors. Norris' company, American
Technology, sells the devices for $600.

http://www.popsci.com/popsci/bown/article/0,16106,388134,00.html


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