NOISE CONTROL DEVICE.

摘要

A noise control device which comprises a speaker (3) arranged in the exit of a tail pipe (2) through which noises of the engine of an automobile are given off, the open end of which is at a given angle with respect to the plane vertical to the ground in the vicinity of the tail pipe (2) in order to silence the noises; an enclosure (21) tightly closing the rear part of the speakers (3 and 4); and a silencing sound guiding member (22) which guides the silencing sound released from the front end of the speaker (3) to the exit of the tail pipe (2). A bumper (23) which absorbs the shock at the time of collision is formed in a closed space. This closed space is used as the back cavities of the speakers (3 and 4). A plurality of microphones (5-1, 5-2, and 5-3) are arranged at given distances from the speakers (3 and 4). Their outputs are synthesized on the basis of the degrees of contributions to deaden noises.