A turbulence-shield for a microphone in a wall-cavity

摘要

A cavity (32) is provided external to a duct or fan discharge (10) in an ANC system such that the duct liner or porous material (11) separates the interior of the duct (10) from the cavity (32). A microphone (16) is located in the cavity (32). Baffles (34) of porous material are preferably located in the cavity (32) so as to divide the cavity (32) into a plurality of chambers (32-1,32-2) to reduce internal flow recirculation in the cavity (32). <IMAGE>