PURPOSE: To prevent the generation of hawling even when microphones and a speaker are arranged on the same plane by adjusting respective sound signals inputted through two microphones by a delay circuit and an amplification adjusting circuit and canceling the signals by a differential amplifier circuit.
CONSTITUTION: Respective sound signals inputted from the speaker SP through the 1st and 2nd microphones MC1, MC2 are processed by the time delay circuit 2 and the amplification adjusting circuit 4 so that the phases and levels of both the signals almost coincide with each other. The outputs of the circuits 2, 4 are inputted to the differential amplifier circuit 5 and canceled. Thereby, the generation of howling can be prevented even when the speaker and the microphones are arranged on the same face.
TAKEYAMA HIROAKI
FUKAGAWA HITOSHI
| JPS6337748A | 1988-02-18 |