<div>Ok. Thanks J-M for clearing that up.<br></div><div>What if you mix up the polarity on one speaker (180 degree phase change), would that matter?</div><div><br></div><div>cheers</div><div>Greger</div><br><div class="gmail_quote">
2010/3/15 Jean-Marc Valin <span dir="ltr"><<a href="mailto:Jean-Marc.Valin@usherbrooke.ca">Jean-Marc.Valin@usherbrooke.ca</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
If more than one speaker receives the *same* signal, it doesn't matter the<br>
number of speakers. It only gets tricky when the speakers are playing slightly<br>
different signals (e.g. from a stereo song).<br>
<font color="#888888"><br>
Jean-Marc<br>
</font><div><div class="h5"><br>
Quoting Greger Burman <<a href="mailto:greger@mobile-robotics.com">greger@mobile-robotics.com</a>>:<br>
<br>
> One thing I can think of is if you are using two or more speakers. If the<br>
> speakers are not at the exact same distance from the mic, you will get more<br>
> than one echo. AEC can not handle that. Try disconnecting all but one<br>
> speaker and see if it makes any difference.<br>
><br>
> cheers<br>
> Greger<br>
><br>
> 2010/3/15 Anton A. Shpakovsky <<a href="mailto:saa@tomsksoft.com">saa@tomsksoft.com</a>><br>
><br>
> > Hello.<br>
> ><br>
> > I have the following situation. AEC is used in network chat software<br>
> ><br>
> > over DirectSound API. Echo and reference signals are almost aligned<br>
> ><br>
> > (delay is no more than 30ms). When echo is emulated in notebook<br>
> ><br>
> > (built-in speakers + mic) everything goes fine and echo is cancelled.<br>
> ><br>
> > But when configuration includes stand-alone speakers and mic no echo is<br>
> ><br>
> > removed. Audio is in 22050 hz at 16 bit mono format, number of samples<br>
> ><br>
> > to process were 441 and tail was used 4096.<br>
> ><br>
> ><br>
> ><br>
> > Dumps are here:<br>
> > <a href="http://rapidshare.com/files/317389207/speex_AEC_test.rar.html" target="_blank">http://rapidshare.com/files/317389207/speex_AEC_test.rar.html</a><br>
> ><br>
> > nb_*** - working configuration (notebook)<br>
> ><br>
> > sa_*** - standalone speakers with no echo removed<br>
> ><br>
> ><br>
> ><br>
> > Can it be because of differences in fixed and arbitrary acoustic systems?<br>
> ><br>
> > I will appreciate any of your advises or thoughts.<br>
> ><br>
> ><br>
> ><br>
> > Thanks!<br>
> ><br>
> ><br>
> ><br>
> > Anton A. Shpakovsky<br>
> ><br>
> > Multimedia Software Developer<br>
> ><br>
> ><br>
> ><br>
> > _______________________________________________<br>
> > Speex-dev mailing list<br>
> > <a href="mailto:Speex-dev@xiph.org">Speex-dev@xiph.org</a><br>
> > <a href="http://lists.xiph.org/mailman/listinfo/speex-dev" target="_blank">http://lists.xiph.org/mailman/listinfo/speex-dev</a><br>
> ><br>
><br>
<br>
</div></div></blockquote></div><br>