| 摘要 |
<P>PROBLEM TO BE SOLVED: To reproduce necessary sound at top volume while suppressing distortion using a compact speaker. <P>SOLUTION: A user specifies reproduction volume output from a speaker (15) using a volume adjuster (16). An object sound signal read from a recording medium (11) is subjected to band limitation by an adaptive bandpass filter (12), amplified thereafter at gain in accordance with the specified reproduction volume by an amplifier (14), and thereafter transmitted to the speaker (15). The passband of the filter (12) is dynamically set in accordance with the specified reproduction volume. The passband is set relatively wide when the specified reproduction volume is relatively small, and the passband is gradually narrowed as the specified reproduction volume is increased. <P>COPYRIGHT: (C)2011,JPO&INPIT |
