A volume controller for controlling volume balance between a front speaker
and a rear speaker located within a vehicle, includes a fade volume
computing unit for computing an amplifying factor k1 of an input signal
for providing an increased volume at the rear or front speaker by the
volume at a prescribed position within the vehicle which is equal to an
decreased volume in the front or rear speaker when a signal supplied to
the front or rear speaker is attenuated by an attenuating factor K1; and
a control unit for multiplying the signal supplied to the rear or front
speaker by k1 when a signal supplied to the front or rear speaker is
attenuated by K1. In this configuration, a volume controller can form an
acoustic field with a sense of realism when volume adjustment is
preformed in a to-and-fro direction.