Disclosed is an audio system including a group of loudspeakers that form a sound field by delivering into a single space sound signals passed through respective ones of a plurality of sound signal channels. This audio system is comprised of two characteristic-variable equalizers that are cascaded to each other to constitute a part of the sound signal channels; a sound field characteristics detecting part for supplying test signals through the sound signal channels and detecting sound pressure in the sound field and thereby obtaining a sound pressure signal; and a characteristics adjusting part for adjusting, based on the sound pressure signal, equalizing characteristics of the characteristic-variable equalizers individually and with respect to each of the sound signal channels. The sound field characteristics detecting part selectively generates test signals of different bands. The characteristics adjusting part adjusts equalizing characteristics of either one of the two characteristic-variable equalizers according to the band of the test signal.