Hello, I have a question about use res with mdf filter. During my experiments with speex mdf filter I observed an interesting thing. If I try to echo remove and mdf is working well (ref is much smaller) and after that the residual echo signal is passing to preprocess, then is no effect (I still hear an echo). However when I modified mdf algorithm (adaptation rate), I had a great map of ref signal but very very small amplitude of filter response. Residual echo was also taken into consideration. This time evrything worked excellent (no echo, only silent). It looks as if better effect is when ref signal is without significant change (out=ref-y, where y is very small and ref much greater). I known that mdf works in frequency domain and signal amplitude is insignificant but that what I obcerved seems little weird. What do you think about this? -- art_ mailto:nesart@o2.pl