Sound Technology

A person hears a voice in her ear, turns around and sees nobody there. No one else has heard it. Or she hears footsteps in a room, the product of an invisible presence. Is her mind playing tricks on her?

A 28-year-old graduate F. Joseph Pompei student who is part scientist and part showman, Mr. Pompei has invented a device that projects a discrete beam of sound in much the same way a spotlight projects a beam of light.

The audio spotlight as Mr. Pompei has dubbed it emits a column of sound enveloped by silence, the way the glow of a spotlight is enveloped by darkness. Someone standing inside the beam emitted from his flat black disk hears the sound loud and clear. Outside the beam one hears silence or, if there are surfaces nearby, faint murmurs from the reflected sound waves. The beams can also bounce off walls to create an impression of the source of the sound.

Daimler-Chrysler has already tried the technology in a prototype truck, so that each passenger can listen to his or her favorite music without the annoyance (and, for the driver, danger) of headphones.

Likewise, imagine sitting at home next to a family member, who's watching some show you detest — but you don't care because you're outside the beam of sound and can't hear it.