[Speex-dev] mdf-res connection

Artur Szklarzewski nesart at o2.pl
Tue Feb 7 10:46:07 PST 2006


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 at o2.pl

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