Adaptive howling suppressor in an audio amplifier system

The acoustic feedback causes a howling phenomenon in an audio amplifier system. This problem does not only annoy hearing but also can damage an amplifier system. The IIR adaptive howling suppressor (AHS) in an audio amplifier system is thus proposed in this paper. The algorithm of adaptive process is achieved by using the variable momentum least mean square (VMLMS). With this algorithm, the performance improvement and higher convergence rate can be success. The proposed AHS, which is placed between a preamplifier section and a power amplifier section, acts as a narrow bandwidth notch filter whose frequency characteristic can reduce a howling spectrum. The simulation results show good improvement in the howling suppression of the proposed AHS system. Moreover, the performance comparisons show that the proposed system is performed over the AHS conventional FIR and FALE structures at the same environment condition.