I've been using some assorted programs that capture the Mixer Out as a large .WAV file, which I can then break / edit / compress. It sound like this will be running in the background, and I don't know how small of a footprint you'll find. For example, (as mentioned above) you can use audacity, set it to record from Wave Out Mix, and then capture the audio that is currently playing to the speakers. I don't think you'll hit a quality issue until you decide to encode - the programs I've used all record the audio as uncompressed .wavs.