[Speex-dev] FW: Echo Cancellation

Ard van Breemen ard at kwaak.net
Thu Aug 26 06:08:48 PDT 2004


On Tue, Aug 24, 2004 at 10:44:49AM -0700, Shana Cooke (Gitnick) wrote:
> I think I am doing something wrong, but I am not sure what. I notice you
> are using two samples - play.sw and ref.sw - which are not included in
> the source. What do they sound like? Is there a place one can pick up
> these files? Is this echo cancellation designed more for musical tones
> instead of actual echoes of speech? I know this is experimental and I
> feel I may be using it in the wrong way.

At least I have some examples of my latest experiments:
It's a shocking 9 megabytes, and contains 3 files:
The source (out.wav) going into the modem, the mixed signal
(in.wav) coming from the modem, and the results (hds.wav) I get
with my latest experiments.

The experiment:
- disable-adaption-rate.patch
- disable-AUMDF-weight-constraints-when-adaption-rate=0.patch
  (hah, no patch yet).
- call, initialize the filter by using impulses (ie. ticking the
  microphone, and humming something).
  adapt_rate=0 until a clear silent line is available, and only
  then I start training.
- save the echo-state
- load the echo-state
- adapt_rate = 0 (so AUMDF-weight constraints is also disabled)
- call and record

upload the samples.

What happens during the recording: I talk to my collegea, and
somewhere during the converstation we switch places.
Eh, yes, there is a big system humming near me.

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