The REX File Format
REX is the native file format of ReCycle. A REX file contains the original audio of the loop, the spces you have appped in ReCycle, and any effects or processing you have added in ReCycle. Saving an audio file as a REX file also reduces the size of the file significally. This is achieved by applying a "nonlossy" compression algorithm to the file when saved, meaning that it does not compromise the audio quality in any way.
Practically all major music software titles support the REX format. Be it music production software like Logic, Pro Tools, Cubase, Sonar, Live and of course Reason, or software instruments such as Native Instruments Kontakt, Spectrasonics Stylus RMX or Digidesign Transfuser. Check your software's specifications for REX compatibility.
The Dr.REX and REX Files in Reason
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 its design enables some truly creative ways to use ReCycled loops.
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 spces around to create the beats you want. This way you can take a drum loop and rearrange it any way you want.
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REX files in Record
You can also use your REX files in Record, by importing them directly onto Audio Tracks in Record's sequencer. When you import a REX file in Record, it is automatically stretched to fit the tempo of your Record song. However, rather than using ReCycle's slices as Reason does, Record's stretches the audio with its built-in time stretch to fit the loop to the song tempo.
Read more about Record here