Noise control device

摘要

A noise control device disposed at the outlet of a tail pipe which emits exhaust noise of an automobile to silence noise from the tail pipe comprises a speaker which is arranged near the tail pipe and of which the open surface has a constant angle with respect to a vertical plane, an enclosure which closes the rear portion of the speaker, and a silencing sound guide portion which guides silencing sounds emitted from the front surface of the speaker to the outlet of the tail pipe. A closed space into which a bumper for absorbing impact in case of collision is made, is used as a resonant-cavity of said speaker. Based on the amount of silencing noise which becomes greater as a plurality of microphones are arranged to be closer to the speaker, the outputs of the plurality of microphones apart a constant distance from said speaker are synthesized.