PURPOSE: To expand the listening position by dividing a stereo audio signal into plural bands to apply phase shift and delay.

CONSTITUTION: Left and right channel audio signals (source) subject to stereophonic recording are inputted to input terminals 1a,1b of an encoder. The band of source is split by filter circuits 6a, 6b, part of the sound of the left channel is mixed to the right channel and the right channel sound is mixed to the left channel via phase shift circuits in common use with delay circuits 7a, 7b. The circuits 7a, 7b are provided with input/output wires 8 mutually and cancel the mixed sound of the left/right channels thereby allowing the sound of the left channel to reach the left ear and the sound of the right channel to reach the right ear. The time difference of the sound reaching the left/right ears is corrected to provide the feeling of the expanded sound thereby providing a listener to obtain the feeling of the presence equal to that at the recording. Thus, the listening position is expanded.