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How to build generative beats with Ableton Live's MIDI effects

Following on from our one-note bassline tutorial, here’s another way to break out of a creative rut and make something interesting using only MIDI effects. 

This time, we're thinking differently about Ableton Live’s in-built MIDI processors, cooking up a variable, generative beat that’ll keep you on your toes while working on the rest of your track.

Get more productivity-inspiring tips and techniques in the June 2018 edition of Computer Music.

Step 1: Our Ableton Live project includes a backing pad and a Drum Rack that’s being fed by five separate MIDI tracks, selected in the MIDI To menus. The MIDI feeding each one is the same, playing a C3 note that lasts a whole bar.

Step 2: Activate the Kick channel. One long C3 note means it’s only playing once per bar. To get ourselves a 4/4 beat, head to MIDI Effects in the browser and drag an Arpeggiator onto the kick channel. Set its Rate to 1/4 and you’ve got a 4/4 kick pattern - simple as that. Now activate the snare channel. Getting this one right is a little more complex…

Step 3: Set up another Arpeggiator at 1/4, or copy the same one over from the kick channel. This time also set Steps to 1 and Distance to +1st. This means that every other note output by the Arpeggiator is transposed, giving us the pattern C, C#, C, C# for our bar. But we don’t want a snare for every kick…

Step 4: Drag a Scale device next in the chain. This helps us repitch or reject certain notes from the MIDI signal. Deselect the lowest left note (C) and hey presto - only the C#s remain, timing our snare on beats 2 and 4. Now for a hi-hat pattern. Copy both the Arpeggiator and Scale devices over to the Hats channel and activate it. Hi-hats are quicker, of course, so set their Arpeggiator’s Rate to 1/16.

Step 5: This time, set the Steps to 2, so that three notes are output from the Arpeggiator in sequence. Make sure the C note is still inactive, and retune the D to a C# (as above), so that only two notes out of every three get through and play the same note. The beat’s getting a bit mechanical, so add a Velocity device after the Scale, and turn its Random parameter to 13. Do the same for the kick and snare.

Step 6: For the Percussion channel, we’ll set up a pseudo-random pattern - that is to say, a random timing of notes but with some rules specified. Add an Arpeggiator to the track, with a Rate of 1/8. Now add a Random device after this. Set Choices to 1, and ensure Scale is still at 1. Random changes the notes it received based on rules you set.

Step 7: With the Chance dial at 0.0%, there’s no chance of the note being changed. If you set it to 100%, the note will certainly be changed. Set it to 50% to give a 50/50 probability. If we add a Scale device and deactivate the changed note, the Chance dial turns into a control for whether the note will be played at all.

Step 8: Finally, place an Arpeggiator (set to 1/4) on the Clap track, set Chance to 49% and Choices to 9. Deactivate some of the first nine notes in the Scale device, and retune others. The clap has a 49% chance of playing, and after that, a certain chance (depending on the Scale settings) of reinforcing the snare at its original note or another note, or doing nothing at all.