Comment 30 for bug 900364

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Sean M. Pappalardo (pegasus-renegadetech) wrote : Re: Microphone input sounds horrible on ALSA with Intel audio devices

Wow, excellent work Val!

On a whim, I just tested on my system again in Audacity and was able to nail down the problem! When I set Audacity to ALSA and mono (1-channel) recording from any mic source, the problem occurs. If I set it to stereo, it sounds fine. This is independent of the project sample rate. Val and others, can you please do this same test?

This may indeed be a PortAudio bug (Audacity uses it as well as Mixxx) in that it's interleaving the left and right audio samples when it should instead be throwing away every other one, but it seems more like a mis-communication between the sound hardware and PortAudio. E.g. PA tells the hardware to open just one audio channel but it still streams two regardless.

The ideal course of action would be to fix this in PortAudio, otherwise perhaps a workaround would be to offer an option in Mixxx to open the mic device as a stereo input.