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 > > >
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. Ifthe> speakers are not at the exact same distance from the mic, you will getmore> 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 iscancelled.> > > > But when configuration includes stand-alone speakers and mic no echois> > > > removed. Audio is in 22050 hz at 16 bit mono format, number ofsamples> > > > 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 acousticsystems?> > > > 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 > > >_______________________________________________ Speex-dev mailing list Speex-dev at xiph.org http://lists.xiph.org/mailman/listinfo/speex-dev
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 > > > > > > >-------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.xiph.org/pipermail/speex-dev/attachments/20100316/7a0c06a9/attachment.htm
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 > > > > > > > > > > > > _______________________________________________ > > > Speex-dev mailing list > > > Speex-dev at xiph.org <mailto:Speex-dev at xiph.org> > > > http://lists.xiph.org/mailman/listinfo/speex-dev > > > > > > > > > > _______________________________________________ > Speex-dev mailing list > Speex-dev at xiph.org > http://lists.xiph.org/mailman/listinfo/speex-dev
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 >>> >> > > > > _______________________________________________ > Speex-dev mailing list > Speex-dev at xiph.org > http://lists.xiph.org/mailman/listinfo/speex-dev
On 2010-03-16 14:22, Josh Gargus 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? :-)Tricky here means that I got it to work in some scenarios, but it likely will not work out-of-the-box and you'd be on your own because I don't have time to help on that.> 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?As long as the spatialization transfer function is constant, then a mono AEC will work. If you only have a few different transfer functions, that may be an option. For time-varying spatialization with many (>2) channels, forget about AEC unless you're willing to spend a *lot* of time on that. Jean-Marc> 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 >>>> >>> >> >> >> >> _______________________________________________ Speex-dev mailing >> list Speex-dev at xiph.org >> http://lists.xiph.org/mailman/listinfo/speex-dev > > _______________________________________________ Speex-dev mailing > list Speex-dev at xiph.org > http://lists.xiph.org/mailman/listinfo/speex-dev > >