SpaceWalk

What it does

A generative chord engine that composes four-voice progressions in real time rather than cycling presets, as an AUv3 instrument or MIDI effect that follows the host transport. Dials set richness, suspension, sparseness, flow, smoothness, surprise and register, single chords can be locked or edited by hand, and a progression exports as a MIDI file. Version 1.2 adds per-voice MIDI out, so bass, tenor, alto and soprano can each drive a different instrument on their own channel, plus beats per bar, a one-bar minimum length, per-voice velocity ranges and user preset folders.

In the demo

Jade drives four SoundBox instances in AUM from one SpaceWalk, one voice each, then sets the same routing up from scratch with a bass, a synth and strings. She changes the beats per bar from four to three to two and saves a user preset. Her original full walkthrough is linked in the description.

Worth knowing

It generates harmony only, no melodies, rhythm or audio of its own. It is iPad only, and GarageBand on iOS has no MIDI effect slot to host it, so a progression has to be exported as a MIDI file and dragged in.