[Speex-dev] added background noise problem?

Scott Roberts scott at heelspurs.com
Mon Sep 6 08:04:46 PDT 2004

Using narrow, wideband, and ultra-wideband encoding on a short 16khz wav
gave .spx's of 3,789 ... 2,935  ... and 1,875 bytes. Even after reading the
manual, smaller files for the higher frequency encoding seems

My mp3 at 32 kbps on the original 22khz wav is 3,866 with a quality
comparable to speex wideband on the converted 16khz wav, so speex is a 24%
improvement in size. The mp3 had a little more (but acceptable) hiss, but
it had better sharpness in the higher frequencies (hence the hiss).
Overall i rank the quality even.  I tried LAME mpeg-2 layer 3 on the
converted 16khz wav, but i still had to go up to 32 kbps (same file size)
to get the same quality as speex wideband.  So all in all, i estimate speex
to have a 25% better quality/size ratio than mp3 on high quality speech.

Maybe a speex expert could do better settings, but maybe so too could mp3.
But maybe implementation by a novice user is part of a valid comparison
even if my methodology isn't perfect.

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