No abstract

In this study we propose a modification of the least mean square algorithm to improve its capacities for the suppression of the acoustical feedback in audioconference rooms. IJsually all the time or frequency domain algorithms are based on a uniform approach of the whole response of the acoustical channel. We propose to introduce an a priori geometrical information on the reponse to divide it into two kinds of coefficients : fast or slow varying ; the step size of the gradient algorithm depending then on the kind of coefficient. This allows a better adaptation, which can be still improved, using an algorithm of detection of motion in the room, to separate stationary and non stationary period.