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....com >> ??????????2010-03-03 >> >> >> >> _______________________________________________ >> Speex-dev mailing list >> Speex-dev at xiph.org >> http://lists.xiph.org/mailman/listinfo/speex-dev = = = = = = = = = = = = = = = = = = = = ????????QianBin ????????cola_tin at 163.com ??????????2010-03-03

On 03/03/2010 10:22 PM, QianBin wrote: > Hi, > > But in fact, it really affects the voice quality. One of my tester says, "Is your mouth far way from the mic?" > Could you explain why we should cut 200hz below? > We already said it affects the quality when the voice is compressed. Are you askin...

Hi Jean-Marc, You make that sound like its just a matter of meeting some arbitrary spec. Let's be more specific..... If you use narrow band voice down to deep bass frequencies: - 16 bit linear audio sounds good - alaw or ulaw sounds muddy - low bit rate codecs, like speex or G.729, sound awful. I assume QinBin only listened to some uncompressed audio in his evaluation.

Hi, The notch filter in AEC is only used to remove DC signal, and the time of convergence is not important, right? If so, I think preset value of notch_radius is too small, and it causes noticeable distortion(freq < 200hz cut). There is a picture in attachment to show signals under different radius in time-domain. By setting notch_radius to 0.999 for all sampling rates, I found better