Microphone arrangement for a breathing mask

摘要

An electro-acoustical transducer device includes a body structure (101) and a differential microphone (102) located in an aperture of a wall of the body structure. The microphone includes a front side for receiving an acoustical signal and a rear side for receiving the acoustical signal in modified form. The differential microphone is arranged to produce an electrical output signal proportional to the difference of the acoustical signals at the front and rear sides. The body structure is arranged to form a chamber (105) shared with the rear side of the microphone. There are tubular channels (107) to the chamber so that the channels and the chamber constitute an acoustical filter for filtering the acoustical signal falling to the rear side of the microphone. With proper design of the chamber and the channels, it is possible to achieve acoustical filtering for background noise rejection.

主权项

1. An electro-acoustical transducer device comprising:
a body structure, and a differential microphone located in an aperture of a first wall of the body structure,wherein:
the differential microphone comprises a front side for receiving an acoustical signal and a rear side for receiving the acoustical signal in modified form, the differential microphone is arranged to produce an electrical output signal substantially proportional to a difference of the acoustical signal at the front side and the acoustical signal at the rear side, the body structure is arranged to form a chamber shared with the rear side of the differential microphone, and there is at least one first tubular channel in the first wall of the body structure to the chamber so that the at least one first tubular channel and the chamber constitute an acoustical filter for filtering the acoustical signal falling to the rear side of the differential microphone, andwherein the electro-acoustical transducer device further comprises a vented cover element allowing both the front side of the differential microphone and the opening of the at least one first tubular channel to receive the acoustical signal in the same form.