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

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

So happy to see someone has looked into this. Thanks fellas.

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!

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...

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?

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.

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.