[Speex-dev] mdf -- better adaption of W?

Thorvald Natvig speex at natvig.com
Thu Dec 15 22:49:02 PST 2005

>> I'll need to add support for saving audio to my program, so I can give you
>> the "actual" sampled loudspeaker and mic files, and I'll also need to get
>> hold of a test person again. (I had a friend with a friend who has an
>> exceptionally clear voice. My own "aaaaaa" is far too muddy to cause
>> this). I'll try to get this done this week, but it might be delayed 'till
>> after christmas.
> Let me know if you have files that cause the problem. Otherwise, it's
> pretty much impossible to debug.

Ah. It seems I made a "minor" mistake. Remember I said I used my 
headset for testing and stuck the microphone into one of it's "speakers"? 
Well.. headsets ARE stereo, and the music it had trouble cancelling was 
music with strong stereo separation -- the residual echo was the sound 
from the other speaker. Which is quite natural.

Same goes for the voice, as we use positional audio. (Helps phenomenally 
to have positional audio when two people try to talk at the same time; 
without positioning it is very hard to distinguish them).

So, redoing the simple tests after adjusting the balance so all the sounds 
came from just the right side, everything worked PERFECTLY.

Sorry for the erronous bugreport :(

Anyway, I found a few papers on multisource echo cancellation. Unless it's 
already a feature on the short-term "TODO" list, I'll take a stab at 
adding simple multisource cancelling after christmas.

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