| 摘要 |
PROBLEM TO BE SOLVED: To provide an automatic sound volume controller preventing sound leakage of a headphone and an earphone, and also preventing a reproduced sound volume from being aperiodically varied. SOLUTION: A microphone 3 provided in the vicinity of a sound output section picks up sound externally leaked to an external auditory meatus from a sound output section 2 being the headphone or the earphone, the frequency of the reproduced sound signal and the frequency of the sound signal detected by the microphone is analyzed, and occurrence of sound leakage is determined when the frequencies matches each other. Then, the volume of the sound signal reproduced by the sound output section is decreased. COPYRIGHT: (C)2007,JPO&INPIT
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