| 摘要 |
PROBLEM TO BE SOLVED: To attain desired directivity by simply changing an inexpensive variable directivity means while sharing not only the microphone body but also the microphone unit. SOLUTION: In a condenser microphone, a microphone unit 100 contains an acousto-electric converter 110 including a diaphragm and a fixed pole in a unit casing 101 having a front acoustic terminal 102. The unit 100 is attached removably to a microphone body 200 where a voice output circuit board 211 is contained in a microphone casing 201 having a rear acoustic terminal 202. A partition wall 220 is provided in the microphone casing 201 to form an air chamber 240 of a predetermined volume between the partition wall 220 and the acousto-electric converter 110, the rear acoustic terminal 202 is formed on the wall surrounding the air chamber 240 along the axial direction, and the directivity under that state is made hyper-cardioid. A variable directivity means for making the distance between the front and rear acoustic terminals variable is contained in the air chamber 240, and the directivity is made cardioid or the condenser microphone is made nondirectional. COPYRIGHT: (C)2008,JPO&INPIT
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