Also, there's a little obscure pair of settings that might be the culprit of Bus 2 and beyond are not working. Do the following:
- Open the Ensemble Pro Server FX window in REAPER. Make sure you are using the VST3i version of the Ensemble Pro Plugin. As far as I'm aware, Ports/Buses beyond #1 won't work in REAPER unless it's VST3 (this might have been fixed in REAPER 6).
- Click on the button in the top right part of the window that says something like "2/64" out. It will open a window with a grid.
- On that new window, click the small button that says I/O, again in the top right. You'll get a drop down menu.
- In that menu, you need to change a few settings. They are:
- Midi Input -> Map REAPER MIDI Buses to VST3 MIDI Buses
- Midi Output -> Map VST3 MIDI Buses to REAPER MIDI Buses
Make sure both those are checked. Once they are, Buses 2 and up will interact correctly with Ensemble Pro, allowing you to have 256 separate instruments in a single Ensemble Pro instance. Yay!