Active acoustic echo cancellation in spatial soundfield reproduction

The equalization of reverberation effects is essential for spatial soundfield reproduction, but estimation of the reverberant channel presents several challenges to existing equalization techniques. This paper presents a method of active acoustic echo cancellation (AEC) for soundfield reproduction applications, using a modal description of the reverberant soundfield. We describe how individual modes of the measured soundfield can be equalized adaptively, thus reducing the complexity of the channel estimation process. AEC and reproduction performance is compared with existing adaptive and non-adaptive equalization techniques through simulation examples. Equalization performance is comparable to existing methods, achieving a normalized region reproduction error of 1% and echo return loss enhancement of 15 - 30 dB at 50 dB SNR. The results suggest that the proposed model can be used to obtain a parallel implementation of a room equalizer for active AEC.