Joined is a sample composition that changes the loudness of each channel with a slider.
I'm no audio expert, so I don't know what is really going on when panning audio channels, if it's not the loudness that should be changed.
Generates a lookup-table to be used with "Apply LUT" node from MM.Filters, or to be exported for use with any LUT application based on GPUImage by Brad Larson.
You might have to connect a "Fire on Display Refresh" node to each of the inputs. As it generates the final LUT by creating loads of gradients up to 4096px x 4096px in size, this can be quite resource intensive if removing the event blocks from the inputs.
Put it in your User Modules folder and LUT LUT and away!