I believe it controls the speed of the Leslie speaker IRL. There is a full b3 preset in presence, I used it quite a bit in SO 2.6 and in 4. Probably been a year since I've used the mod wheel, now I can't get it to operate. Presonus forums showed some similar complaints, but no solution. Its really an essential part of the b3 sound to my ears and I haven't been able to automate a fix, which would be pretty inconvenient anyway.
I never used 2.6. I went through a bunch of my organ settings in Presence with my keyboard and none of them respond to the Mod Wheel, which I would expect, since the Leslie sound isn't isn't actually a part of Presence, but instead is a plug-in.
However, you can make it work as you describe pretty easily.
Open a new song.
In the channel lane, drag in a copy of Presence.
Make sure your mixer is open.
Drag the Rotor Speaker plug-in into your mixer Inserts list for the Presence channel.
Check to confirm that S1 is seeing your mod wheel. In the upper left hand corner of the main channel window, you should see something like this.
It may be named something else. My keyboard is a really old M-Audio Oxygen 61 and doesn't have a template within Studio One, so I previously built the template and the mod wheel has already been named. On my keyboard it is Control 8 and I have named it 8-Mod Wheel.
To be certain you are seeing the mod wheel, move the mod wheel. If the number in the lower right corner of the box changes with movement of your mod wheel the software is monitoring your mod wheel.
Once you know the mod wheel is being recognized, open your Rotor plug-in and click on the Rotor Speed Switch.
That will change the upper left display to say Rotor and Speed.
Then click the left pointing triangle between the Rotor (left) and Mod Wheel (right)
That should globally link the control in the software unless you change it.
