acoustical coupler

7.01  acoustical coupler. Cavity of specified shape and volume used for the calibration of earphones or microphones in conjunction with a calibrated microphone adapted to measure the sound pressure developed in the cavity.

Annotation         Acoustical couplers are specified in ANSI/ASA S3.55-2014/Part 1/IEC 60318-1:2009, ANSI/ASA S3.55-2015/Part 3/IEC 60318-3:2014, and ANSI/ASA S3.55-2014/Part 5/IEC 60318-5:2006.