Abstract
The purpose of this study is to develop an anti-howl back device in karaoke. An acoustic feedback path of such a microphone speaker system is generally varing when the microphone is moving. Then the impulse response was instantaneously estimated by the LMS algorithm, using music source. The feedback signal was canceled by an adaptive filter which realized the impulse response. By using this system, the acoustic feedback was proved to be attenuated. But some important issues remained.
