[Speex-dev] AEC strangest behavior

[Greger Burman]

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?

cheers
Greger

2010/3/15 Jean-Marc Valin <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>:
>
> > 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>
> >
> > >  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
> > >
> > >
> > >
> > > _______________________________________________
> > > Speex-dev mailing list
> > > Speex-dev at xiph.org
> > > http://lists.xiph.org/mailman/listinfo/speex-dev
> > >
> >
>
>
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