[Speex-dev] AEC strangest behavior

[Josh Gargus]

On Mar 15, 2010, at 8:46 AM, Jean-Marc Valin wrote:

> 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).
> 


Does "tricky" mean that the Speex AEC won't handle such situations well?  Or just that you had to be extraordinarily clever in order to make Speex AEC handle such situations well?  :-)

We're thinking of using Speex AEC in the context of a virtual environment using OpenAL for spatialized sound.  Is there any hope that this could work?  What could we do (short of not spatializing sound input) to make things easier for the AEC algorithm?

Thanks,
Josh



>  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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