Abstract: A reverberation system produces reverberant sound supposed to be generated when sound emitted from a real sound source location inside a virtual acoustic room to be simulated is reflected by virtual room partitions surrounding the same, based on a set of stored impulse responses of reverberant sound actually or virtually observed at different observation positions in the vicinity of room partitions defining an actual or virtual model acoustic room. Digital filters each convolute a source signal representing the emitted sound, using coefficient parameters representing the corresponding stored impulse response, to thereby synthesize a virtual reverberant sound signal at each of simulation positions corresponding to the observation positions.