THE PLUGIN · BETA
THIRI VST, in beta
A harmonizer that voices what you play with THIRI's rules, in real time, inside your DAW. Type a chart, play, and the voicings follow it. It is the same voicing engine as the API, so a chord asked for in the plugin and a chord asked for over MCP come back the same.
- VST3 for macOS, tested in Ableton Live 11 (26 September 2026)
- Three tabs: PERFORM, CHART, TRIGGER
- Chart box up to 64 bars, locked to the host transport
- Free during the beta
The three tabs
PERFORM
Play, and THIRI voices it. The plugin tracks what comes in, from MIDI or from a horn or a voice through the pitch tracker, and plays the voicing back under the same rules the API uses. Pick a voicing type, a key and a mode; the chord-aware voicings (drop3, jazz, scale, chord) listen to the chart, the key voicings (thirds, open, drop2) follow key and mode and ignore chords, and the tab names which one is listening.
CHART
Type a progression such as Em7 | Am7 | B7 Em7 | Cmaj7. A bar ends at a bar line or a new line, chords inside a bar split it evenly, an empty bar holds the previous chord, and the box takes up to 64 bars with a bars: N / 64 readout as you type. The first SET applies at once; every later SET lands at the top of the next loop, so a change typed mid-phrase arrives on beat one. With the host clock the chart is a chord track whose bar 1 is Live’s bar 1.
TRIGGER
One MIDI note sets the chord. With a chart loaded, pad n is bar n: C1 is bar 1, up to bar 64, which is exactly the 64 pads on a Push. With no chart, the pad’s pitch class is the root and the trigger quality is the chord. Note off is ignored, so the chord holds until the next press; CLEAR, PANIC, CC120 or CC123 drop it. Three or more distinct pitch classes inside 35 ms are read as a played grip.
The full behaviour, including how Live files the plugin and the two-instance rig, is in the manual chapter Ableton and DAWs.
What the beta includes, and asks
- The VST3 build for macOS, free for the length of the beta.
- The install walkthrough above and the manual chapter.
- A direct line for feedback: what worked, what did not, in which DAW and version.
- We ask for that feedback, and that you do not redistribute the build.
- AU and Windows builds may come later. They are not promised.
Where it is going: MCP and the DAW
- Phase A Ableton Live, over the AbletonOSC bridge: the chart and the transport in both directions.
- Phase B The plugin as a local MCP endpoint, so any agent can set the chart and read the voicing in any DAW.
- Phase C Other DAWs natively, once the bridge has proved the shape.
Tick the second box below to hear about this first.
Already in the beta? Tell us how it went.
Apple Silicon
The beta build is Intel (x86_64). On an Apple Silicon Mac, run your DAW with Rosetta (Finder, Get Info on the app, tick Open using Rosetta) and the plugin loads as usual, or wait for the universal build.
Lab builds
CORIS, a voice harmoniser in the browser, and HORN SXTN, the horn harmoniser on the Elk Stomp, are lab builds, not for sale. Read how HORN SXTN got onto the pedal or try the engine live at demo.thiri.ai.