1. Go Insert > ReWire Devices > Reason; when the Insert Soft Synth Options dialog box appears, specify the audio outs. Check MIDI Source to create an accompanying MIDI track, and check Synth Property Page so you can see Reason’s GUI. Click on OK.
2. Create a ReDrum device in Reason, load a drum kit into it (click on the folder button), and select the ReDrum track in Reason’s sequencer so that incoming MIDI data feeds ReDrum.
3. Select the Sonar MIDI track that drives ReDrum. Assign this track’s output to Reason, and its channel (via drop-down menu) to ReDrum.
4. With the desired MIDI track selected in Sonar, go Views > Step Sequencer.
5. The Step Sequencer’s note assignments should default to the notes for ReDrum (MIDI notes 36–45). If not, re-assign them, or load an appropriate drum map.
6. Click on the Step Sequencer steps where you want to trigger drums, and hit the Step Sequencer’s Play button. Sonar will create a loop that starts at the Now time, and lasts for as long as you have steps in the Step Sequencer. Now program your sequence!
-In Step 1, when specifying audio outs, “First Synth Audio Output” provides the mixed stereo out. This is usually sufficient, as you can do your drum mixing within ReDrum.
-In Step 2, if there are any warnings about MIDI inputs not being found when you open Reason, ignore them.