Python Multi-Channel Audio

[Alex Karpinski]

I'm looking for some module or system of modules that can help me do a few things with audio

1. Playback of files (at least .wavs, other codecs would be nice but, hey, converting to a wav is easy)
2. Seek within the file
3. Control volume
3. Do all of these things by channel, e.g. play sound effect 1 on channels 1&2 at equal volume and play effect #2 on only channel 2

I've got a setup with gstreamer and alsa right now, but I don't have any way of getting control of individual channels at the gstreamer level. I can easily do it at the alsa level and just manipulate the master left/right output, but that's not very helpful if it modifies all currently playing effects. I'm not even sure if this is possible to do with python, butsome pointers would really be great. 

(For the curious: This is part of the audio system for a larger immersive theater project, )