AutoArp is a Rack Extension for Propellerheads Reason. AutoArp is a music assistant that will help you make music, regardless of your experience level. Easy to start using, yet offering deep customization, it is a powerful toolkit to assist musicians of every type.

AutoArp provides Scale mapping, a Chord Generator and an advanced Arpeggiator with a Step Sequencer.

AutoArp: Make Music!


Input Control

  • Hold for "Latch" effect
  • Quantization options for first input, note changes, and release
  • Multi-Note modes override the chord generator for "traditional" arpeggiator operation
  • CV Sequencer Control inputs to allow AutoArp to be controlled via CV

Scale Mapping

  • 12 keys and over 60 scales with "Audition Scale" mode to aid choosing the right scale for your song
  • Notes played are snapped to the current scale allowing improvisation that's always in key
  • Custom mapping allows alternate chord triggering for more variation

Chord Generator

  • Integrates with scale mapping to ensure progressions are in scale
  • Chord inversion
  • Custom chord creation
  • Over 60 chords in the chord dictionary to serve as reference in creating custom chords
  • 3-octave chord "trimming" option allows further customization of how each chord sounds


  • Shuffle timing with custom shuffle group size
  • "Human" timing for a more natural sound
  • Extend your chords for longer arpeggio patterns
  • Velocity variation
  • 7 Play Modes: Linear, Skip, Skip Rev, 3-1, 3-1 Rev, 4-2, 4-2 Rev
  • 6 Play Directions: Up, Up+Down, Down, Down+Up, Random, Manual
  • Play Count setting to loop arpeggio or play only 1-4 times (for "One Shot")
  • Option-rich Repeat Note setting designed from common guitar playing technique but capable of many variations for any style

Step Sequencer

  • Display allows visualization of pattern and doubles as a step editing aid
  • Individual step timing to create unique rhythms
  • Steps can play individual notes or chords
  • Individual step note selection allows custom pattern creation

Multiple Outputs

  • Control multiple instruments with one AutoArp instance via sequencer control outputs for Single Note, Chord, and Main
  • Arpeggio Playing output triggers on pattern loop
  • Sequencer Step output conveys timing of sequencer to trigger other instruments like Kong/Redrum drum sounds
  • Performance control-to-CV outputs


  • AutoArp's removable faceplate operates as a tablet computer to allow editing AutoArp patches on the go*


Beta Testers


* Since AutoArp is not a physical hardware device, the "removable faceplate" is a conceptual reference to the planned future release of a tablet version of AutoArp which will read and write .repatch files allowing patches to be edited/created on the tablet and then loaded into AutoArp Rack Extension. Details and release date TBA.