Comparison of multichannel doubletalk detectors for acoustic echo cancellation

In acoustic echo cancellation (AEC) a doubletalk detector (DTD) is typically used to avoid misconvergence of the adaptive filter during simultaneous activity of near-end acoustic scene and loudspeaker playback. While several single-channel DTDs can be generalized to multiple channels, only little attention was so far paid to the evaluation of the resulting multichannel DTDs. In this paper, different DTDs are reviewed and evaluated. In particular, the influence of the number of loudspeakers is investigated as new dimension in the experimental evaluation, where up to sixteen loudspeaker channels are considered. The results show that the performance of a DTD is affected by the number of loudspeaker channels whenever the cross-correlation between the loudspeaker signals is considered by the DTD. Moreover, considering this cross-correlation turned out to be necessary for a high detection performance.