摘要 |
Apparatus for attenuating noise particularly in an aircraft cabin, comprises a diaphragm (10) one side of which is subjected to the noise, sensing means (16) for sensing the displacement of the diaphragm in response to the noise, and deflecting means (20) responsive to the sensing means for deflecting the diaphragm in order to cancel the displacement, to attenuate noise transmitted from one side of the diaphragm to the other side of the diaphragm. |