for the last half-year or so that I've been using asterisk, I could throw any sort of mp3 at moh: vbr, stereo, high bitrate -- anything, and it would still sound very good over the wire. but recently I called my home system and was greeted by over-loud, distorted moh. the culprit: my recent upgrade of mpg123. permanently resampling my moh mp3s to 8khz seems to be the only workaround. I think there was some security issues in 0.59r, elst I'd just downgrade back to it.