| 摘要 |
A unitary housing made from an acoustically-opaque, resilient material is employed with a microphone element to form a directional microphone assembly. The microphone element includes a diaphragm which moves under the influence of sound pressure applied to its opposite surfaces to generate an electrical signal which is proportional to the differential sound pressure. The unitary housing includes a first acoustically-transparent channel for communicating sound pressure from a first port in the unitary housing to one surface of the diaphragm, and a second acoustically-transparent channel for communicating sound pressure from a second port in the unitary housing to the other surface of the diaphragm. An illustrative embodiment, the unitary housing comprises a unitary small "boot " having a surface including the ports for coupling acoustic energy to the acoustic channels, an inner chamber for housing the microphone element and a predetermined opening in a surface of the boot for accessing the inner chamber. The microphone element is inserted into the inner chamber via the predetermined opening, which is dimensioned to seal itself around the inserted microphone element so that acoustic energy cannot leak out of or into the inner chamber through the opening. The distance between the ports is relatively short so as not to change the directivity pattern or frequency response of the resulting microphone assembly. In the illustrative embodiment of the invention, the unitary housing is molded from Ethylene-Propylene-Diene-Monomer with Polypropylene which is a rubber-like material that is resilient. It forms an excellent seal around the perimeter of the microphone element so that sound pressure in one channel does not leak into the other. Moreover, the rubber-like material forms a seal with the surface of sound-input equipment where it is housed.
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