Comment 34 for bug 900364

Sean: the mono/stereo issue you observed in Audacity may indeed be somehow related to this Mixxx issue. The audio card that performed well in my tests was the only audio card with mono Alsa input. All other audio cards in my tests had stereo Alsa input, and that's where the bad mic sound problem was observed. The detailed hardware info on my audio cards can be found in the linked zip file in post #29 above.

It may be just a coincidence. I have no other audio hardware to test this hypothesis. Hopefully, somebody else here will be able to test whether mono/stereo Alsa input is what makes the whole difference.