Ableton Forum

I was djing with Live at a house party last night, and using my partner's MacBook Pro and an Evolution/M-Audio X-Session. We keep the crossfade mapped to the crossfade, obviously, and other knobs mapped to other effects. We keep one knob mapped to the master tempo. We started our set with that set to a range of 75-95 bpm, but later wanted to bump it up even faster. So I changed the range to 95-115, moving the knob back to the left while still in the blue midi screen. But then upon trying to change the tempo, the knob elicited no response. For the rest of our set we had to change the tempo manually, which worked, but is obviously very much less than ideal. The unusual thing is that all of the other control mappings continued to work - we could still crossfade, adjust EQ, etc.

Anyone have any idea why this would have happened? My first thought was that it was because the X-Session was unpowered, but that would have affected all the controls, right?