Patent ID: 8511428

Claim:
A noise attenuator which reduces noise transmitting in a duct, comprising: a pair of circular through holes formed through a duct wall; a pair of wave transmitting/receiving membranes which are stretched so as to close the respective circular through holes, receive a sound wave, and vibrate; a seesaw member which connects between central portions of the paired transmitting/receiving membranes and is pivotally supported with respect to the duct so as to be capable of transmitting vibration between the paired wave transmitting/receiving membranes; a central leg provided on the seesaw member and having a distal end pivotally supported on the duct wall; and an interference avoiding recess depressedly formed in the duct wall so as to avoid an interference with the distal end of the central leg, wherein the paired membranes and a pivot center of the seesaw member are coplanar with each other.