Guide to ReWiring Reason into P5

Learn how to start using P5 and Reason together and work around certain limitations.

By Danny Adler (SuperGreenX)

What You Need

Basic ReWiring

  1. Open a project in P5.
  2. Add a new instrument track - At the top of the track pane, there should be a button with a keyboard icon and down arrow. Click that and select 'DXi and VST Devices' on the right, then 'Rewire Devices.' Reason (and any other ReWire slave capable application) should be listed. Click on Reason. A new track labeled Reason should appear. Alternatively you can right-click an empty area in the track pane, select Instert Instrument > ReWire Devices > Reason. You can also create a new empty track or change an existing track by clicking on the blue Add Instrument button in the track inspector.
  3. Now, you either need to start Reason manually, or double click the word "Reason" in the blue box inside of the track inspector for your Reason track. Press play in either P5 or Reason and you should see the now time cursors in both programs moving forward. This way you know the two programs have synced up properly and are operating correctly.
  4. Begin building up your rack in Reason as you usually do, adding mixers, instruments, and effects. When it comes time to control the Reason instruments in P5 via midi, remember this: only the first 16 machines added to Reason can be controlled via P5's ReWire MIDI. More on this limitation is below. Say that you've built a typical starting rack: you've got the Hardware Interface at the top (it's always there), a mixer, and some instrument (Lets make it a Subtractor for now). This would make your Subtractor instrument #3. Remember this.
  5. Go into P5, select your Reason track, and view it in the track/bus inspector. Under MIDI input, click the 'midi send to' pulldown menu. Since the Reason Subtractor is the third device in the rack, you must control it with Channel 3. Select channel 3. Now, when you click on notes in the piano roll, or set the Reason track to recieve your external device midi input, the subtractor should play. You can now sequence the Subtractor just like any other software synth in P5.
  6. If you want to add more Reason instruments, add them in the Reason rack and keep track in what order you added machines. In P5, right click the Reason track and select 'create layer.' A new MIDI layer will pop up. View it in the track inspector and select the midi channel that corresponds to the Reason instrument you want to control. This track should now control the new Reason device you selected.


In P5, in the track that corresponds to the Reason machine you want to automate, click the show automation button. Under 'MIDI,' select the CC number that corresponds to the parameter on the Reason machine that you would like to automate. Unfortunately, only some of the basic parameters are labeled. To find out the CC number for your parameter, you will need to look it up in the MIDI Implementation Chart PDF that installed along with Reason. Select the correct CC number, and your automation in P5 should control your Reason device.

Project5 Reason ReWire Limitation

P5 (Cakewalk SONAR, also) can only control the first 16 devices added to the Reason rack via ReWire MIDI. Even if the user creates 17 Reason machines and moves the 17th one from the bottom of the rack to the top of the rack, that machine is still the 17th machine and cannot be controlled via P5. Even the hardware interface which has no controls takes up a channel, so in reality, you can only control the first 15 machines you create in Reason.


Reason 3.0 - The best workaround for Reason 3.0 users involves the Reason Combinator device. It is also effective for SONAR users. Create a template rack for ReWiring that is comprised of one mixer and 14 combinators. When adding instruments, make sure absolutely everything you add is inside of a Combinator. This way, the mixer and Combinators are the first 15 machines added to the rack and therefore you can control them via ReWire MIDI. This also makes any effects you add inside of the Combinators automateable without taking away from your ReWire MIDI Channels. Automation is less of a hassle also, since when you link parameters on a Reason machine to the knobs and buttons on the Combinator, you only need to know MIDI CC numbers for those four knobs and four buttons.

For Reference the Combinator CC numbers are:

MIDI Yoke - MIDI Yoke is a free driver made for internal computer MIDI routing. You can find it and more information . Reason can take intput from 4 busses of 16 midi channels (totalling 64) and all are assignable to which instrument you want. You use the hardware mixer at the top to select busses and which midi channels control what Reason machine in your rack. P5 will send midi out to the MIDI Yoke channels and Reason will recieve them. Unfortunately, I cannot go into detail with the procedure to do this, as I have not attempted this with P5 yet (I did it in SONAR a long time ago). You may need the free RGC Audio MIDI Out DXi plugin to send the midi out of P5. I do know that functions such as freeze and exporting of Reason instruments will not work with the Reason instruments you are controlling. You must first record to audio in real time into a new audio track, then export the song.

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