A sub woofer system is constituted of a real time digital signal processing part 5 that includes an A/D converter 5a, a low pass filter block 5b, a delay block 5c, and a D/A converter block 5d, an analog power amplifier 6 and a speaker 7. The length of delay time of the delay block 5c is set so that...http://www.google.fr/patents/US6771784?utm_source=gb-gplus-shareBrevet US6771784 - Sub woofer system
