Response curve for Live Send Pot?


    Mar 05 2012 | 9:39 am
    Hi all,
    does anyone have information regarding the send pots in Ableton Live?
    I'm trying to build an equal-power panning system for an 8-channel application and have found that the send pot is not truly logarithmic. In fact, it looks like it's modelled on a "real life" log pot.
    Does anyone know what function Ableton use to produce this response?
    best wishes
    richard

    • May 16 2012 | 10:18 am
      OK. In case this is of use to others, I'm going to answer my own question:
      The Live Send pot is neither linear nor truly logarithmic.
      This is of particular importance if you are using it for an equal-power application like panning. Multichannel spatialisation devices like [Max Api SendsXnodes] and [Max Api SendsPan] that control Live Sends via the API and do not address this issue produce a marked drop off in level when sounds are panned in-between speakers in multichannel environment.
      I talked to Ableton who say the design is procedural and not given to a mathematical solution, so I did some measurements and produced a lookup table (antipot.aif) to make the necessary corrections.
      Here is the .aif file and a small example patch.
      I have also applied this technique to a couple of audio-rate M4L devices which I will put up online soon.
      best wishes
      Richard
    • May 16 2012 | 3:43 pm
      Hi Richard,
      I ran into this exact same issue earlier this week trying to implement equal power quad panning in Live. It drove me nuts for a while because all the sources and tutorials I found online claiming to do this seemed to get it wrong.
      I ended up using the curve~ subpatcher from the Max Api SendsPan device. If I remember correctly a value of about 0.83 gave me - 3db between speakers.
      Thijs
    • Jan 05 2013 | 7:12 am
      So happy to see someone has looked into this. Thanks fellas.
    • Oct 09 2015 | 7:46 pm
      While developing my m4l patch I experienced the exact same problem, your solution solved it all for me. What a remarkable way to do it also! Cheers Richard, this was amazing, and saved my day!
    • Oct 10 2015 | 9:49 am
      Thé problem is exactly the same with the volume faders and we never got a clear answer from Ableton. I started a thread, amongst others, at least three years ago...
    • Oct 10 2015 | 11:05 am
      if you have two options: build your own slider or wait for several yers until someone else will do it for you, what option will you choose?
    • Oct 11 2015 | 9:14 am
      I'll build it. The fact is I like to know how things work, specially when I explain something iin a workshop. Just was totally surprised that we can't get any official word about this.
    • Apr 06 2017 | 10:44 am
      Thanks Richard !
      I didn't found your implementation so I built one.
      Here is a very simple Max For Live device controlling 4 sends and using the "antipot.aif".
      I included the antipot.aif in the folder, make sure the audio file stays in the same folder than the amxd.