Acoustic feedback path modeling in active noise control systems

The presence of strong acoustic feedback degrades the convergence speed of the active noise control (ANC) filter, and in the worst case the ANC system may become unstable. Here we present an overview of the existing methods developed to neutralize the effects of acoustic feedback. We identify the problems with the existing methods, and propose a new method. The proposed method uses three adaptive filters; a noise control filter, a feedback path modeling (FBPM) filter, and a third filter. The third filter works on the principle of adaptive noise cancelation (ADNC) and its objective is to remove disturbance from the desired response of FBPM filter. In comparison with the existing method, which works only for narrowband noise, the proposed method can work with both the narrowband and broadband noise sources. The computer simulations are carried out, which show that the proposed method performs better than the existing methods in both, the noise control performance, and FBPM performance.