| 摘要 |
PROBLEM TO BE SOLVED: To rationalize a load amount of a power source, and to suppress generation of abnormal sound and sound quality variation of reproduced sound. SOLUTION: As a load reflection amount of a power unit 800, an ammeter unit 110 detects the total amount of current flowing out from the power unit 800. Then, a coefficient calculation unit 120A calculates an attenuation coefficient CEF based on a detection result by the ammeter unit 110, and lowpass limit processing corresponding to the calculated attenuation coefficient CEF is performed by volume control units 140<SB>L</SB>, 140<SB>R</SB>. In the lowpass limit processing, an attenuation amount of a component in a frequency region near a lowpass resonant frequency with high impedance of a speaker unit 170<SB>j</SB>is made small, and an attenuation amount in other frequency region in a low-pitch band with low impedance of the speaker unit 170<SB>j</SB>is made large. COPYRIGHT: (C)2009,JPO&INPIT
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