Audio Spotlight
Saturday, 8 September 2001
In mid-July, Showsound hosted a demonstration of a new sound technology known as the Audio Spotlight. The device, which was demonstrated by inventor F. Joseph Pompei, represents what the company believes to be the first successful development of a truly directional loudspeaker. Whereas a traditional loudspeaker produces a large field of sound, the Audio Spotlight emits a narrow beam of sound - as little as just 3° at 3m.

In practice, the Audio Spotlight generates a beam of sound that can be accurately pointed at specific locations. People within the field of the beam will hear clear audible sound, whilst others standing just outside will not. The sound can be aimed directly at targets or reflected off almost any surface in a method known as Projected Audio.

Joseph Pompei has developed this innovative new system at the Massachusetts Institute of Technology’s Media Laboratory. A significant number of the devices have already been built, and new manufacturing techniques are about to see the production scale increase to meet the anticipated demand. Showsound will distribute, install and operate the patents-pending Audio Spotlight in the UK and Europe.

How it Works
The Audio Spotlight uses ultrasound generated by specially developed transducers that are fired into the air. The natural non-linear properties of air interfere with the ultrasound, breaking down the very short sound waves into different ultrasound patterns along with outputs within the audible sound range. The effect of the air on the projected narrow beam of ultrasound is not random and can be mathematically predicted.

Pompei’s breakthrough is based on his system’s ability to alter audible sound signals (such as those from a CD player) before they are emitted by the ultrasound transducer in such a way as to allow the reproduction of clear, audible sound after interaction with the air. The Audio Spotlight effectively uses the air itself to generate audible sound from ultrasound waves along the path of a narrow beam.

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