Looping 101: Reason's Dr. Rex Loop Player

Reason is a virtual rack of synthesizers, samplers, effects, mixers and more, combined with an easy-to-use sequencer. Reason’s Dr. Rex Loop Player lets you easily play loops in time with other tracks and instruments in Reason.

Dr. Rex plays REX2 files—a special type of audio loops created in Propellerhead’s ReCycle software. ReCycle “slices” a loop into a series of separate samples that correspond to the individual drum hits—resulting in a REX2 file. REX2 players such as Reason’s Dr. Rex module can play back the loop at any tempo because each sliced sample is fired independently. This separate treatment of each drum hit allows for manipulation of the swing of the timing as well. You can also manipulate the pitch and even the contents of the individual slices to mangle the original into something unique.

Working with loops in Dr. Rex is really simple. After loading Reason, use the Create menu to open a Mixer 14:2 and a Dr. Rex module. Click the Browse button (the folder icon), navigate to your loops library and open one. Click the Preview button on Dr. Rex and you should hear the loop play back at Reason’s current master tempo. Change Reason’s master tempo if you want your groove to be faster or slower. Click the Preview button again to stop playback.

While previewing the Dr. Rex module, try experimenting with the rest of the controls in the module. Some like those on the far right apply to the entire loop. Others apply only to what is currently selected, which you can select by simply clicking on the desired slice. Of course, you can also go back and browse for a different REX2 file.

Reason lets you layer multiple loops by employing several Dr. Rex modules simultaneously. First, click the To Track button on your existing Dr. Rex module. This sends the data that fires the series of slices to the first track on your sequencer at the bottom of the screen. Now use the Create menu to open another instance of Dr. Rex. Use the Browse button to open another loop in the second Dr. Rex. Experiment with the new loop in the same way as you did the first. When you are satisfied, click To Track to send the performance data to a second sequencer track. Now both will play when you click Reason’s play button. Experiment with changing the Tempo and Pattern Shuffle controls.

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