Thanks for your help. I'll go through the section of the manual you noted. I can't at the moment seem to get anything out of channels 3/4, it's just 5/6 in ableton that have anything coming in, 3 and 4 are silent (and 1 and 2 are my laptop's own microphone). I've got the asio driver which I can access through ableton and it recognises and labels the x3 live as you'd expect, next to my laptop's sound card. (However Ableton just has the inputs labeled as numbers, not 'USB' followed by a number as you describe). I set the inputs in the x3 as guitar for tone 1 and aux for tone 2, still the mic and guitar both come through together in inputs 5 and 6 in ableton. The quick fix I did was to hard pan both tones in the x3 output settings, that makes it possible to record the guitar and mic into separate audio tracks in ableton. I must be doing something dumb, I'll keep at it.