SILENCER

摘要

PROBLEM TO BE SOLVED: To provide a silencer for efficiently silencing low-frequency stationary sounds over a wide range. SOLUTION: Speakers 8a to 8d are arranged in proximity to a noise source 2 generating the noises having thtree-dimentional directivity in a contactless state. The noises from the noise source 2 are collected and microphones 10a to 10d collect noise signals. A controller 12 receives input of at least the noise signals and forms and supplies the silencing signals of the antiphase from the phase of the noise signals and of equal amplitude to the respective speakers independently from each other with each of the speakers. COPYRIGHT: (C)2004,JPO