Abstract: The present invention was developed in order to realize a multi-channel sound system wherein appropriate output (balance and fader) control can be conducted without adversely affecting the program contents, and a sound system, which can reproduce a plurality of channel signals including at least left and right front channels and a center channel for forward-placed speakers, comprises a gain controller to control the gain of either left or right channel signal and a gain controller to control the gain of the center channel signal depending on the gain control of the left or right channel signal.

Abstract: As in a compartment of an automotive vehicle, when a left- and a right-channel loudspeakers are disposed at angularly different positions from each other with respect to a frontward direction of a listening position, there will be formed a sound field laterally asymmetric with respect to the frontward direction of the listening position. In order to correct the asymmetry of the sound field, a crosstalk signal obtained by correcting the phase and the level of an acoustic signal of the left-channel from an acoustic signal source and a crosstalk adjustment signal obtained by correcting the level of the acoustic signal of the left-channel are fed to the right loudspeaker, or a center loudspeaker disposed between the left and right loudspeakers, together with an acoustic signal of the right-channel from the acoustic signal source.

Abstract: When a stereophonic broadcasting signal is interrupted because an electric field has weakened, a pilot signal 1 which designates that the electric field is not strong enough to separate an R-channel signal and an L-channel signal from a signal received by the tuner, is also interrupted. This interruption of the pilot signal changes gains and/or phases which act on an R-channel signal and/or an L-channel signal which are applied to a sound field calibrating system.

Abstract: A coefficients setting method of a plurality of parallel connected comb filters whereby a delay time is set to the delay device provided with each comb filter to flatten reverberation frequency and to remove high frequency in the rear part of reverberation. The multiplying coefficients are set to multipliers provided with each comb filter to obtain the common reverberation time in the rear part of reverberation to improve the quality of reverberation sounds.