| 摘要 |
PROBLEM TO BE SOLVED: To provide an on-vehicle acoustic reproducing device for a low frequency band which produce optimum acoustic output even in the case when the level of noise in the cabin changes by the traveling of the vehicle. SOLUTION: When the vehicle stops, a voltage control amplifier 505 detects whether an engine stops or idles. At the time of idling, the amplifier 505 lifts an amplification factor and when the vehicle travels, a frequency voltage converter 501 detects the velocity of the vehicle to control the amplification factor of the voltage control amplifier 502 so as to obtain an optimum acoustic output signal corresponding to the velocity of the vehicle. Thereby, the optimum acoustic output in a cabin is obtained. |
