ReWire Tutorial Article ProTools - Step 2: Routing MIDI
Via ReWire you are not limited to transmitting only audio from Reason to ProTools, you can also send MIDI from ProTools to Reason. This way you can control everything from ProTools - in effect, Reason becomes a rack of devices that you play from the Rewire host! Or, if you like, you can have Reason's sequencer play some of the devices and the sequencer in ProTools play some - it's up to you.
1. In Reason, create the device you want to play.
2. In ProTools, create a MIDI track.
3. Pull down the MIDI Output menu for the track in the Mixer. All devices in the current Reason Song are listed on the pop-up menu, along with the conventional, "physical" MIDI outputs.
4. Select a Reason device from the pop-up menu. The output of the MIDI track is now routed to that device.
If you enter some MIDI notes on the track and hit play, you will hear them being played by this Reason instrument device. This works just as if each Reason device was a stand-alone hardware MIDI sound module.
You can also play Reason instruments "live" this way, by selecting the proper MIDI input for the track in ProTools (the input to which your MIDI keyboard is connected). All incoming MIDI is immediately sent to the track's MIDI Output - the Reason device.
Step 3: Using multiple ReWire channels