I just remembered this and thought that it might come in handy for some of you.
One of the nice things about DJing with Ableton is the ability to set loop points on the fly. This is kind of compensated for by the fact that you can’t set hard cue points, something that people who are coming from Traktor or other DJ programs often points out. That, however, is a story for another day.
In the sample pane of the clip view (down at the bottom of the screen) you will see that, next to the Loop position and length, there are buttons marked set. Now:
Trigger the clip.
Press the “Set” button next to position to set the start point of the loop.
Press the “Set” button next to length to set the endpoint.
You can release the loop by clicking the “Loop”
Alternatively, you can set the loop length ahead of time and just set the start time when the mood hits you.
Map these three buttons to a MIDI Controller and you can jam these babies on the fly.
The thing that I remembered, though, is that you can control the quantization of the loops! This means that you can be sure that, whatever happens, it will only loop starting on the downbeats, or 16th notes, or whatever.
All you have to do is pay attention to the master quantize up in the Master transport bar up at the top middle of the screen. It is the dropdown menu next to the pen icon. The quantize of the loop set control will follow that master quantize.
Good luck and happy mashing! Let me know in the comments if this post helps or if you have any other cool DJ techniques.