Did you know that you can use AAX plug-ins as MIDI Effects in Pro Tools? AAX plug-ins can receive MIDI events, modify them, and send them to another plug-in. Yes, it’s possible!
As an example, let’s see how to apply a simple MIDI effect on incoming MIDI events to control a virtual instrument. We are using here Blue Cat’s Plug’n Script, a plug-in that lets you write your own audio and MIDI scripts, for both the MIDI effects and the virtual instrument:
- Create an Instrument track with the virtual instrument that will receive MIDI events
- Add the MIDI effect on the same instrument track (in a slot before the virtual instrument)
- Create a MIDI track to route events from the MIDI input to the MIDI effect.
- Create a MIDI track to route events from the MIDI effect to the virtual instrument
- Arm both tracks for recording
Using the setup above, you can play “live” the instrument and record the performance on the MIDI track. Once this has all been recorded, an extra step is required before playback, because events will have been recorded twice (the original MIDI events on the first track, and the MIDI events after the MIDI FX on the other track):
- Remove MIDI events that have been recorded on the second MIDI track (events transformed by the MIDI effect).
- The first MIDI track does not need to be armed for recording (it will just play recorded MIDI events), but the second track that route events from the effect to the virtual synth has to, so that Pro Tools actually routes the events.
- Hit play: the MIDI effect is applied to recorded MIDI events and control the synth!
As you may have understood, if you want to use many MIDI effects at a time, making connections and enabling/disabling monitoring with all these additional MIDI tracks can become frustrating. So if you want to make things simpler, you may want to do all MIDI routing inside Blue Cat’s PatchWork. This does not limit you to VST or Audio Unit virtual instruments, since the PatchWork plug-in lets you route MIDI events to its own AAX MIDI output, but you should be able to use just a single MIDI track instead of many, if you want to chain MIDI effects.