The Dr.Rex Loop Player is a truly unique machine that has become one of the cornerstones in Reason's intuitive musical workflow. It plays loops treated by Propellerhead Software's ReCycle and it's design enables some truly creative ways to use ReCycled loops.
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To fully understand Dr.Rex you need to understand what it means to ReCycle a drum loop. Imagine that you have a sample of a drum loop that you want to use in a track you are working on. The loop is 144 bpm and your track is 118 bpm. What do you do? You can of course pitch down the loop, but that will make the loop sound very different, and what if there are harmonies in the loop that you want to match to your song. You can also time stretch it. That will keep the pitch, but will make the loop sound different. Usually it means that you loose some 'punch' in the loop.
Enter ReCycle and the smart way to make loops tempo independent. Instead of stretching the sample, ReCycle slices the loop into little pieces so that each drum hit (or whatever sound you are working with) gets it's own slice. ReCycle also creates a MIDI file with the slices played the way the loop was originally played. These slices can be exported to an external hardware sampler or saved as a REX file to be used in Cubase or... Reason!
When the loop has been sliced you are free to change the tempo any way you want. You can also create fills and variations since the slices can be moved around in the sequencer. More information about ReCycle can be found here and audio examples of general ReCycle tricks can be found here.
Dr.Rex can play REX and .rcy files created with ReCycle. When you open a new ReCycled loop in Dr.Rex you can load up the corresponding MIDI data in a special REX editor in the sequencer where you can move the slices around to create the beats you want. This way you can take a drum loop and rearrange it any way you want as illustrated in the examples below.
A basic drum loop from Sounds Good's Sounds & Cycles
Using the original loop above, we have created variations and fills by moving slices around.
The combination of slices, a filter and a filter envelope creates some unique possibilities for the experimental producer. The filter and amplitude envelopes triggers on each slice and that means you can have filter sweeps and envelope effects on each slice as illustrated in this example:
Using the loop from previous examples we have added effects by tweaking the filters, filter envelopes and amplitude envelopes while playing.
In addition to the filters and envelopes there is also the possibility to set pitch, pan, level and decay for each slice. This can create some very interesting effects when used on instrument loops. Remember that you don't have to limit yourself to drum loops. Any rhythmic sample will do as you can hear in this example.
A synth loop from Sounds Good's Sounds & Cycles
By setting pan, pitch and level for each slice, the result can be quite different from the original loop. Ok, we couldn't stop ourselves from using the filters and envelopes too.
Tips, tricks and more info about Dr.Rex can be found in the Ask Dr.Rex issue of our Discovering Reason article series.