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<p class=MsoNormal><span lang=EN-US>Hi All<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>We are working on an ARM-based speaker
phone application where the speaker and microphone is placed roughly 8 cm from
each other (similar to this one: http://www.voipsupply.com/images/CHAT50SPLASH.jpg).
<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>We are using Speex AEC and preprocessor to
handle the acoustic echo. The AEC typically contribute with ERLE of 15-20 dB which
should be as expected from the algorithm. Additionally we need about 30 dB echo
suppression which we hope to get from the preprocessor.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>However it has shown to be very hard to make
the speech switching reliable under situations where the far-end signal is very
strong compared to the near-end signal in the mic signal (rec). We have converted
the AEC and preprocessor code to matlab and are able to look at all signals. We
can modify the Qcurve-function to bring more attention to the near-end signal
or we can modify the echo_noise estimation (add gain and accumulation) to bring
more attention to the residual echo suppression. However it is hard to optimize
for both.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>My question is if anyone have any tips of
how to make speex preprocessor work in systems like ours (with speaker and mic
close to each other) or if anyone have a reference of success/failure of such
implementation.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Best Regards<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Johan <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
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