What is the RX2 file format?
.rx2 files contain audio loop samples in the REX2 format - a proprietary format developed by Propellerhead Software AB (now Reason Studios). The contents of .rx2 files are audio loop samples whose playback tempo can be adjusted without pitch-shifting artifacts.
Unlike the older REX format, which could only store 16-bit mono samples, .rx2 files can contain both monophonic and stereophonic audio at up to 24-bit depth. The format stores loops pre-sliced at transient points - each hit or beat becomes a discrete slice - so a DAW can stretch or compress the loop tempo by adjusting the spacing between slices rather than time-stretching the waveform itself.
Samples from .rx2 files can be used directly in a sequencer or digital audio workstation (DAW), enabling the creation of audio tracks that include loops at any tempo. Dedicated software can change the playback tempo as well as layer in new loops imported from .rx2 files.
REX2 was introduced in 2001 with ReCycle 2.0, superseding the original .rex/.rcy format. Propellerhead opened the REX2 specification to third-party DAW developers in 2012, enabling broad native support in Ableton Live, Cubase, and Pro Tools. The standalone ReCycle application was discontinued in the early 2020s, but .rx2 remains widely supported in Reason Studios’ Reason DAW and all major hosts that adopted the open specification.
Security & safety
RISK: LOWREX2 is an audio loop format with no executable content. Safe to open in any DAW. Download loop libraries from reputable vendors (Loopmasters, Sample Magic, etc.). No known security issues with the format.
Format details
in a nutshellPrograms that open RX2 files
Windows4 apps
Avid Pro Tools
Freemium Import .rx2 via Clip > Import Audio; Pro Tools renders slices to the session tempo automatically. 
Reason Studios Reason
Paid Drag the .rx2 into a Dr. Octo Rex player or the Browser - natively supported as the original Propellerhead format.
Steinberg Cubase
Paid Drag the .rx2 to the Project window; Cubase imports REX2 loops and maps slices to tempo.
Cockos REAPER
Paid Import via File > Import Media; REAPER supports REX2 natively. Affordable license. 
macOS4 apps
Avid Pro Tools
Freemium Import via Clip > Import Audio or drag to the timeline; REX2 slices are preserved. 
Apple Logic Pro
Paid Drag the .rx2 into the Tracks area; Logic recognizes REX2 and follows project tempo. 
Ableton Live
Paid Drag the .rx2 from the Browser into an Audio track; Live imports REX2 and warps the slices to project tempo. Technical details
deep spec| Format type | Sliced audio loop (binary, proprietary) |
| Developer | Propellerhead Software AB (now Reason Studios) |
| Byte order | Big-endian |
| Audio bit depth | Up to 24-bit (REX v1 was 16-bit only) |
| Sample rate | 44.1 kHz or 48 kHz (typical) |
| Channel support | Mono and stereo (REX v1 was mono-only) |
| Compression | Lossless proprietary, ~2:1 to 2.5:1 ratio on complex loops |
| Typical file size | 500 KB - 20 MB |
| Tempo range | 20-450 BPM (stored in binary header) |
| Header metadata | Stores tempo, time signature, bar/beat count, and slice count before audio data |
| MIME type | audio/x-rex2 |
| Loop slicing | Pre-sliced at audio transients; each slice stored with start/end timing offsets |
| Third-party spec access | Opened by Propellerhead to DAW developers in 2012 |
| Supported platforms | Windows, macOS |
| Supersedes | .rex / .rcy (REX v1 format, 16-bit mono only) |
| Released | 2001 (ReCycle 2.0, introducing the .rx2 extension; superseded the original .rex/.rcy format) |
| Latest version | REX2 (since 2001; format unchanged; spec published by Propellerhead 2012) |
| Specification | www.mixonline.com |
RX2 conversions
Community Q&A
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