Environmentally protected microphone for an active noise control system

摘要

An air introduction system (10) includes an active noise control system (22) having an environmentally protected microphone (24). A microphone support structure (26) defines a louvered cage (38) over a microphone reception cavity (40). The microphone (24) is mounted to a circuit board (42) which fits within the microphone reception cavity (40). A cover (42) fits into the cavity (40) to encase the microphone (24) therein. An open cell foam (60) surround the microphone (24) and a waterproof material (58) encases the foam (60). The waterproof material (58) includes an excess of material such that waterproof material provides for internal air expansion and contraction. By locating the foam (60) between the microphone (24) and the waterproof material (58) improved transmission of acoustic waves is provided which thereby maintains microphone sensitivity.