I'm running two midi tracks within Ableton's session view. One track is a NI Massive instrument containing the midi notes that play within the song ("LIVE KEYS BACKUP") and another is an instrument rack with the same NI Massive synth sound ("LIVE KEYS"). Is there a way to have both play at the same time, but for the midi note track to cut out if keys are pressed on a live midi keyboard? Essentially having a backup track so the part is still played even if I don't play that part on the keyboard, but with the freedom to still play it if I choose to.

Current Setup

[11/11/2015] - As suggested in the comments the monitor could be switched between "In" and "Auto" to achieve this. It's possible to do this automatically on keypress of a midi note using M4L but I have no prior experience with this. Something like the suggested pseudo code below is what I'd like to achieve:

if (a midi note is played)

CC = 0 //turn to **in**


CC = 64 //turn to **auto**

2 Answers 2


To "mute" a track when there's audio coming out of some other track, you can use sidechain compression. Here's how to do it:

  1. Insert a Compressor on the "LIVE KEYS BACKUP" track
  2. Select the "LIVE KEYS" track as the sidechain input
  3. Set Ratio to the maximum
  4. Set Threshold to the minimum

If you now have a clip playing on the "LIVE KEYS BACKUP" track and you play notes on the "LIVE KEYS" track, you'll notice the BACKUP track will "mute".

Further, you can use Attack to control how long it takes for the BACKUP track to mute once you start playing and Release to control how long it takes for it to "unmute" once you stop playing.

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You could assign one of your midi Pad/switch on your keyboard (if you have one) to the monitor section.Then switch between in(when you play) and auto(when your midi clip is playing). Set the midi signal scale of your cotroller from 0 to 64 .

This way you could avoid having two different tracks and save some CPU/Memory.

This process could be done automatically using softwares like the Lemur or even Max/MSP. In pseudo code this would look a bit like this:

if (a midi note is played)

CC = 0 //turn to in


CC = 64 //turn to auto

  • Hi Jonhatan, I've got max for live installed but have barely any understanding of it. Do you know how you'd make this with Max for Live? I assume it'd be a MIDI effect of some kind?
    – AshHenbrey
    Nov 11, 2015 at 4:15
  • Sorry but I would Love to help you on that but I don't know how to use Max. You can always change the title of your post and put the tag Max/Msp. I just know you can do that with Max. Cheers
    – JSmith
    Nov 11, 2015 at 11:13

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