PURPOSE: To correct easily a sound field with simple constitution by providing plural processing units performing processing, generating noise in one processing unit with a desired characteristic and allowing the other processing units to use the desired characteristic for spectrum analysis of a signal.

CONSTITUTION: When preset pushbuttons 1411∼1413 and a pushbutton 14S for set control are depressed, the mode of sound field measurement is executed by digital signal processing units (DSP)13L and 13R. The DSP13L generates a pink noise at first. Then the other DSP13R analyzes spectrum. A band-pass filter corresponding to f1∼f8 bands is formed in parallel in the other DSP13R and the filter outputs are integrated respectively. Each integrated value corresponds to the acoustic characteristic of the place where a speaker and a microphone are placed. Thus, the acoustic characteristic is measured in this way and the value corresponding to the complementary characteristic is written in a RAM19.