| 摘要 |
PURPOSE:To improve an S/N by providing an M period sequence signal generat ing means, M period sequence response possessing means, impulse response restoring means and acoustic correction data setting means for correcting fre quency characteristics, balance and arrival time. CONSTITUTION:An M period sequence signal is generated from one speaker, and that response is possessed by a double ear microphone at a hearing position. In this case, the response is possessed by a right ear microphone 81 when right side speakers, namely, speakers 71 and 73 are reproduced, and the response is possessed by a left ear microphone 82 when left side speakers, namely, speakers 72 and 74 are reproduced. Next, the calculated response of an M period sequence is restored into the impulse response by M period sequence transformation. Next, high-speed Fourier transformation is performed to that impulse response, and the frequency characteristic is calculated. Finally, that frequency characteristic is analyzed, and an equalizer correction coefficient for executing desired improvement is set. Based on that correction coefficient, a base sound frequency characteristic inside the vehicle is corrected by an equalizer. |
