Imagine standing in the frozen-food aisle of your supermarket, staring at a tub of your favorite double-fudge brownie ice cream. Suddenly, a voice comes out of nowhere to tell you there's a two-for-one sale on that very treat. But only you hear the message. In fact, the guy studying the cookie-dough choices 2 feet away is listening to a different ad--which you can't hear.
This scenario would be right at home in the dreamlike ad sequences of Steven Spielberg's Minority Report. But so-called directed sound may soon be accosting consumers in all kinds of real-life settings. A small San Diego company, American Technology Corp. (ATC), has already begun shipping a product called the HyperSonic Sound system, which uses inaudible ultrasonic waves to create vibrant sound out of thin air. Its inventor, Elwood G. "Woody" Norris, believes it could be used in everything from military communications systems to home electronics. "What if you could watch TV in bed at 1 a.m.," he muses, "and aim the audio just at yourself, so your sleeping spouse hears nothing?"