Noise cancelling microphone for full coverage style helmets

摘要

Noise cancelling microphone construction for placement in a full coverage style helmet to secure and hold a noise cancelling microphone in the plenum between the inner liner and outer shell of the helmet, the construction having a front boot and a rear boot. The front boot has a speech receiving front open sleeve leading to front ports of the microphone, a flat annular flange attached to a cylindrical end of the front sleeve, and a second sleeve attached at one of its cylindrical ends to the other side of the flange, the second sleeve securing the front part of the microphone, the flange and second sleeve encompassing an opening in the helmet inner liner. A box formed on the front sleeve receives noise in the helmet environment, passes the noise through an opening in the annular flange and through the opening in the helmet inner liner. The rear boot has a cylinder with one closed end to hold and secure the rear part of the microphone, and an elongated sound passageway attached to its outside communicating with the cylinder interior through an opening. The sound passageway conducts noise from the front boot box to the rear ports of the held noise cancelling microphone. Thus noise present within the helmet environment is conducted to the noise cancelling ports of the microphone to cancel like noise entering the front ports of the microphone.