vibration isolation

10.67  vibration isolation. Reduction achieved in the ability of a system to vibrate in response to a mechanical oscillation through the use of a resilient coupling. Annotation              See also 4.24.

shielding

10.66  shielding. Phenomenon whereby sound reduction is provided by interposing a wall or partition between a sound source and a receiver.

insertion loss

10.65  insertion loss. Of a silencer or other sound-reducing element in a specified frequency band, the decrease in sound pressure level measured at the location of the receiver when a sound insulator is inserted in the transmission path between the sound source and the receiver. Unit, decibel (dB). Annotation              See also 6.71.

duct lining

10.64  duct lining. Layer of porous material placed on the inner surface of a duct to attenuate sound that propagates through the duct.

critical frequency

10.63  critical frequency. Of a panel or partition, the lowest frequency at which the coincidence effect occurs. Unit, hertz (Hz).