| 摘要 |
PURPOSE:To emphasize a low frequency portion of an amplitude characteristic by using a resistor, a capacitor and an amplifier to form a positive feedback high pass filter and setting the Q at 1.0 or over. CONSTITUTION:An output of an acoustic signal source 13 is inputted to a positive feedback high pass filter 14. The positive feedback high pass filter 14 consists of resistors 17-20, capacitors 21, 22 and one operational amplifier 23 and the contacts of the resistors and the capacitors are adjusted to set the Q of the high pass filter at 1.0 or over thereby providing a peak to the amplitude characteristic near a low frequency cut-off frequency and the low frequency characteristic is emphasized. The output is fed to a power amplifier 15 and reproduced from a speaker 16, then a deficient low frequency sound is corrected. Thus, an in-cabin acoustic characteristic with balance in medium and high frequency sounds and flat characteristic is obtained. |
