[Speex-dev] AEC strangest behavior

[Jean-Marc Valin]

On 2010-03-16 06:35, Greger Burman wrote:
> Ok. Thanks J-M for clearing that up.
> What if you mix up the polarity on one speaker (180 degree phase
> change), would that matter?

Not at all. It's still all linear. You can even apply a different 
equalizer to each speaker and it'll still be linear.

	Jean-Marc

> cheers
> Greger
>
> 2010/3/15 Jean-Marc Valin <Jean-Marc.Valin at usherbrooke.ca
> <mailto:Jean-Marc.Valin at usherbrooke.ca>>
>
>     If more than one speaker receives the *same* signal, it doesn't
>     matter the
>     number of speakers. It only gets tricky when the speakers are
>     playing slightly
>     different signals (e.g. from a stereo song).
>
>        Jean-Marc
>
>     Quoting Greger Burman <greger at mobile-robotics.com
>     <mailto:greger at mobile-robotics.com>>:
>
>      > One thing I can think of is if you are using two or more
>     speakers. If the
>      > speakers are not at the exact same distance from the mic, you
>     will get more
>      > than one echo. AEC can not handle that. Try disconnecting all but one
>      > speaker and see if it makes any difference.
>      >
>      > cheers
>      > Greger
>      >
>      > 2010/3/15 Anton A. Shpakovsky <saa at tomsksoft.com
>     <mailto:saa at tomsksoft.com>>
>      >
>      > >  Hello.
>      > >
>      > > I have the following situation. AEC is used in network chat
>     software
>      > >
>      > > over DirectSound API. Echo and reference signals are almost aligned
>      > >
>      > > (delay is no more than 30ms). When echo is emulated in notebook
>      > >
>      > > (built-in speakers + mic) everything goes fine and echo is
>     cancelled.
>      > >
>      > > But when configuration includes stand-alone speakers and mic no
>     echo is
>      > >
>      > > removed. Audio is in 22050 hz at 16 bit mono format, number of
>     samples
>      > >
>      > > to process were 441 and tail was used 4096.
>      > >
>      > >
>      > >
>      > > Dumps are here:
>      > > http://rapidshare.com/files/317389207/speex_AEC_test.rar.html
>      > >
>      > > nb_*** - working configuration (notebook)
>      > >
>      > > sa_*** - standalone speakers with no echo removed
>      > >
>      > >
>      > >
>      > > Can it be because of differences in fixed and arbitrary
>     acoustic systems?
>      > >
>      > > I will appreciate any of your advises or thoughts.
>      > >
>      > >
>      > >
>      > > Thanks!
>      > >
>      > >
>      > >
>      > > Anton A. Shpakovsky
>      > >
>      > > Multimedia Software Developer
>      > >
>      > >
>      > >
>      > > _______________________________________________
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>      > > Speex-dev at xiph.org <mailto:Speex-dev at xiph.org>
>      > > http://lists.xiph.org/mailman/listinfo/speex-dev
>      > >
>      >
>
>
>
>
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