| 摘要 |
PROBLEM TO BE SOLVED: To provide a narrow variable directional microphone in which the pointing angle of sound pickup can be changed as desired by covering an acoustic resistance hole with an acoustic resistor having a freely adjustable acoustic resistance. SOLUTION: An acoustic resistance hole 23 provided in the length direction of a sound tube 22 is covered with an acoustic resistor 32 formed of an elastic material 33 and a hard thin plate 34 arranged on the surface thereof such that the acoustic resistance of the acoustic resistor 32 can be adjusted by pressing the elastic material 33 against the hard thin plate 34 and adjusting compression of the elastic material 33. Consequently, the pointing angle can be narrowed by strong compression against the acoustic resistor 32 and can be widened by weakening compression. COPYRIGHT: (C)2008,JPO&INPIT
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