Because of the introduction of additional poles to the system by acoustic feedback channel, there exists the possibility of unstability of ANC system.

This paper first explores the causes of the acoustic feedback, and then presents 5 effective ways to prevent it: scientific design of the interior acoustic; the proper choice of sound amplifying instrumnts; the arrangement of the cabinet speaker system; strictly scientific modulation adn correct operation.

The acoustic feedback even howling is a well-known problem in sound reinforcement system.

The reasons and the treatments of acoustical feedback in the multimedia report hall;

And the acoustical feedback of the secondary source is one of the key problems that affect noise reduction in ducts.

This article discusses the producing mechanism about sound feedback of loud-speaking system inside room and the methods and skills of restraining it.

This article analyses the causes of producing sound feedback in multimedia integration classroom and the common methods of eliminating it.