Patent ID: 8130973

Claim:
A superdirectional acoustic system comprising: a sound source for supplying an audio sound signal; a signal isolating device for isolating an audio signal in a medium to high frequency sound range and an audio signal in a low frequency sound range from the audio sound signal supplied by the sound source; a carrier wave supplying device for generating and outputting a carrier wave in an ultrasonic frequency band; a modulating device for modulating the carrier wave by the isolated audio signal in the medium to high frequency sound range, and outputting a modulated signal; an ultrasonic speaker for reproducing the audio signal in the medium to high frequency sound range by using an ultrasonic transducer which converts the modulated signal into a sound wave having a finite amplitude level; and a low frequency sound reproducing speaker for reproducing the isolated audio signal in the low frequency sound range, wherein the modulating device does not modulate the carrier wave by the low frequency signal.