  In this paper, we address an important problem in high-quality audio
communication systems. Acoustic echo cancellation with stereo signals is
generally an under-determined problem because of the generally important
correlation that exists between the left and right channels. In this paper, we
present a novel method of significantly reducing that correlation without
affecting the audio quality. This method is perceptually motivated and combines
a shaped comb-allpass (SCAL) filter with the injection of psychoacoustically
masked noise. We show that the proposed method performs significantly better
than other known methods for channel decorrelation.
