To provide an acoustic system by which an appropriate sound field can be easily set.

Wave receiving elements 1a-1c still stand on a body of a stereo set 4 and on each of its speakers, and receive ultrasound waves transmitted from a wave transmitting element 2. A controller 5 finds the three-dimensional coordinates of the wave transmitting element 2 according to the ultrasound waves received by the wave receiving elements 1a-1c after finding the correct sonic speed. The controller 5 then reads out set data corresponding to the three- dimensional coordinates from its hard disk, generates control data according to the read-out set data, and supplies them to the stereo set 4. The stereo set 4 sets the sound volume, the time-lag, the sound volume of high-pitched and low-pitched sounds and the like of its right and left speakers by adjusting the equalizer, the DSP and the like according to the supplied control data.