| 摘要 |
PURPOSE:To reproduce voice signals in an excellent tone quality even if a speaker is installed in a duct where acoustic transmission characteristics are not flat by correcting the transmission characteristics in a reproduction system. CONSTITUTION:A speaker 23 is installed in an air conditioner duct 11 so as to radiate sound waves, and a digital filter 14, which uses inverse characteristics to acoustic transmission characteristics from the speaker 23 to the air conditioner duct blowoff port side end terminal 12 as its coefficient, is arranged in a speaker driving circuit system. After being digitalized, voice signals are corrected by means of the digital filter 14, and are analogized by means of a D/A converter 15, and the speaker 23 is driven by means of an amplifier 22. |
