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MIDI Mutator

MIDI Mutator is a collection of tools to modify any aspect of a MIDI sequence: rhythm, timing, accents, chords&voicings, and shape.
Designed for modern and pop music producers.
Available for Windows (VST, VST3) and macOS (VST, VST3, AU) with native Apple Silicon support.


Drop a MIDI pattern on MIDI Mutator to start transforming it into a new original pattern! Fully replace or slightly modify the rhythm with a single click. Experiment with other chord voicings, or replace the chords. Bass lines, chord patterns work equally well. The new MIDI sequence can be dragged directly to your DAW, or stored with a single click.


• regenerate the rhythm using 6 rhythm generator algorithms from RapidComposer, plus a new one that preserves exact note and rest lengths, suitable for modern genres
• use rhythm from another MIDI file
• slice a pattern, then rearrange slices randomly
• displace notes randomly, randomize note positions and/or lengths
• extend, widen, randomize chord voicings, replace the chord progression
• change the beat positions to change the feel 
• replace or randomize accents 
• increase/decrease polyphony
• randomize pitches
• for monophonic phrases: change the contour, add connecting notes.
• simple activation. No internet connection is required for activation or operation 

Download demo version

Windows: download installer (VST, VST3)
(system requirements: Windows Vista/7/8/10 (32-bit or 64-bit), DAW with VST or VST3 support)
macOS: download installer (VST, VST3, AU)
(system requirements: macOS 10.11 - 12.0 (Intel or Apple Silicon), DAW with VST, VST3 or AU MIDI FX support)

No internet required to run the demo or full versions.