| 摘要 |
PROBLEM TO BE SOLVED: To provide an earpiece capable of flattening frequency-to-noise sound output characteristics from a low-frequency range to a middle to high frequency range. SOLUTION: Disclosed is the earpiece which has an electroacoustic transducer, a front air chamber, and a rear air chamber, where a sound wave generated by the electroacoustic transducer is propagated in the front air chamber space and output to the outside from a plurality of sound holes bored in an earpiece wall portion. A rear air chamber body is provided with a first leak hole and a second leak hole, and the sound wave generated by the electroacoustic transducer is leaked to outside the receiver to increase sound output in the low-frequency range. When an opening of the first leak hole is covered with a damper material, the sound output of middle-range frequencies decreases to decrease the increase/decrease rate of the sound output with frequencies in a range nearby the middle-range frequencies and also widen the middle-range frequency range (band) wherein the sound output increases, so the frequency-to-sound output characteristics can be flattened from the low-frequency range to the middle to high-frequency range. COPYRIGHT: (C)2008,JPO&INPIT
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