| 摘要 |
PROBLEM TO BE SOLVED: To provide a condenser microphone unit having an acoustic mass effective for passing sound waves at a low-frequency region from the front side to the rear side of a diaphragm to prevent wind noise. SOLUTION: A groove 221 having prescribed acoustic mass in a pipe shape at an area to an end plate 10a of a unit case 10 is formed at the side of the other end face 22b to which the diaphragm 21 of a diaphragm support ring 22 has not been stuck; a first opening 22 for introducing one portion of sound waves from a front acoustic terminal hole 11 into a groove 221 is formed at the inner-periphery surface side of the diaphragm support ring 22; a second opening 223 open toward the inner wall surface of the unit case 10 is formed at the outer-periphery side of the diaphragm support ring 22; the second opening 223 is acoustically connected to the rear side of the diaphragm 21 via a spacer 40; and low-frequency sound waves from the front acoustic terminal hole 11 are guided to the rear side of the diaphragm 21 via the groove 221 having prescribed acoustic mass, thus making pressure equivalent before and after the diaphragm 21 at a low-frequency region. COPYRIGHT: (C)2009,JPO&INPIT
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