[Speex-dev] AEC strangest behavior

[Anton A. Shpakovsky]

I haven't tried yet trick with removing one of standalone speakers as
Greger told,
But I thought of decorrelation. Can it make some influence to the signal
despite of 
I'm using mono format? I tried modifying testecho app, but got
unresolved externals to
All of speex_decorrelate_* functions. It's weird, because
libspeex/libspeexdsp are included in 
Linker options. And one thing that is more weird to me is that I
couldn't find definitions of ANY 
of this functions! What am I doing wrong? 

Thanks.

-----Original Message-----
From: speex-dev-bounces at xiph.org [mailto:speex-dev-bounces at xiph.org] On
Behalf Of Jean-Marc Valin
Sent: Monday, March 15, 2010 9:47 PM
To: Greger Burman
Cc: speex-dev at xiph.org
Subject: Re: [Speex-dev] AEC strangest behavior

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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