On the Use of Forward Gain Switching for Acoustic Howling Control

Several techniques have been introduced over the years to mitigate the effect of howling sound production in sound reinforcement applications. The algorithmic computational complexity of the howling controllers directly affects their implementability on resource-constrained hardware platforms. This work introduces a computationally cheap acoustic howling control algorithm that requires a single multiplication operation for its implementation. The algorithm was modelled, simulated and tested using MATLAB® to obtain its performance metrics. Simulation results showed that the developed technique has average sound quality indices of 1.1746 and 1.2118 for speech and audio signals respectively. Also, for speech and audio signals, Maximum Stable Gain (MSG) Increase figures of 11.29 dB and 9.858 dB were obtained respectively. These results showed that, compared to the standard Adaptive Feedback Control (AFC) technique, the developed algorithm has comparable MSG Increase figures, negligibly small computational cost and low sound quality. This result implied that the howling controller can be easily implemented on a resource-constrained hardware platform at the expense of some degradation in sound quality.