DonutStudio features: tuning, DAW, video & MCP

Every note gets its pitch from its links

Every note's frequency comes from its link chain. You draw a tuning relationship between two notes (a perfect fifth as 3/2, a natural seventh as 7/4, any ratio at any harmonic) and the engine retunes them as exact frequencies. Move a master note and every note linked to it retunes with it. Link two notes and their tuning is set automatically, with no manual per-note microtuning. 12-TET is the starting point, and just intonation, EDO, and arbitrary ratios all work the same way.

Composition

The free workstation tier.

Harmonic piano roll

Draw notes on a piano roll that treats tuning as a graph. Link chains carry ratios across the whole piece; move a master and every linked note follows.

JI-aware chord detection and auto-link

Chord templates built from the harmonic series. Auto-link from a chord lays down a perfectly tuned voicing in one gesture; progression-aware retuning keeps every chord in the same harmonic context.

30+ note transforms

Quantize, humanize, retrograde, legato, staccato, transpose, scale velocity, set track, mute, set cents offset. Batch transforms run in one undo step over a selection or the whole project.

Clip arranger

An arranger page with audio + MIDI clips, automation lanes, tempo maps, and per-track volume, pan, and mute/solo. MIDI and audio recording are both built in.

DAWproject import / export

Read and write the open DAWproject exchange format with microtuning preserved. Move a piece into Bitwig, Reaper, Studio One, or back without losing ratios.

Sound engine

Instruments, effects, and an instrument store.

Sybil-16 virtual-analog synth

Sixteen-voice analog VA synth with full ADSR, modulation matrix, and the same microtonal playback the rest of DonutStudio has. Pitch drifts with the tuning.

OP-7 FM synth (20,800+ presets)

Seven-operator FM synth with a deep preset library. OP-7 plays 12-TET, just intonation, and EDO without re-tuning.

SF2 / SFZ soundfonts

1,300+ instruments, GM-compatible, microtonal playback. Drop a soundfont in, browse presets, audition with the correct tuning.

480+ Airwindows effects + Donut Devices

Chris Airwind's full catalog (console emulations, dynamics, harmonic treatments, time effects, mastering) plus a Donut Devices layer of clean utility effects. All effect chains carry the JI context through.

VST3 and CLAP plugin host

Drop any VST3 or CLAP instrument or effect into a track. Hosted plugins receive the right tuning, and DonutStudio's per-note cents offset propagates into the host via MTS-ESP when available.

In-app content store

Browse and install instruments and effects without leaving the app. Pro-only content is gated by license.

Video (free tier + Pro)

A real editor on the beat grid.

Free beat-synced NLE

Import, cut, warp-to-tempo, color-grade, scopes, LUTs, transitions, text, frame interpolation, export. The free video editor is a full non-linear editor.

Score-reactive Media Machine (Pro)

Generative visuals driven by notes, microtonal tuning, JI ratios, and harmonic content. The visuals read the score, modulating generators and effects with per-note data, harmonics, and clock.

Notation

Score view, in beta.

HEJI / ups-and-downs microtonal notation

Staff-notation overlay that draws accidentals as up/down arrows. HEJI is in beta; the score view renders JI and EDO natively.

Dynamic hierarchies

Choose which notes are shown in the score and how they are grouped by hierarchy. Useful for printing lead sheets in just intonation.

Agent-driven (MCP)

Exposed to AI agents by design.

MCP server on port 9900

JSON-RPC over HTTP. The full editing surface (notes, links, transports, tracks, instruments, pitch bends, batch transforms, file I/O, checkpoints) is callable from any MCP-compatible client.

`arbit` Lua scripting API

Same surface, callable from Lua scripts. Drop scripts into the install directory; they show up in the in-app menu.

Agent skills (Claude Code, Cursor, Codex)

Ready-to-use agent skills for the major coding agents, plus a DonutStudio Video Editing skill. See /donutstudio/agents for the canonical entry point.

Try it on your own piece

DonutStudio Free is a full harmonic DAW. Download it for Windows, macOS, or Linux.

Download DonutStudioAPI & scriptingFor AI agents

Related pages

Inline links to every page an AI agent or non-JS client might need. The page top nav (Features … Download) is JS-rendered from data/projects.json:donutstudio.subnav.

  • Features: /donutstudio/features — every major feature in one place.
  • API & scripting: /donutstudio/api — the public arbit scripting surface, MCP server reference, and links to docs/, examples/, skills/.
  • For AI agents: /donutstudio/agents — how to start, what you can do, example tasks, do/don't.
  • About: /donutstudio/about — one-person project in Denmark.
  • Download: /donutstudio/download — installers for Windows, macOS, Linux.
  • DonutStudio overview: /donutstudio — the home page.
  • MCP server port: localhost:9900 (JSON-RPC; the same surface the arbit Lua API exposes).
  • Public docs on GitHub: https://github.com/DonutsDelivery/donutstudio/tree/main/docs
  • Agent skills on GitHub: https://github.com/DonutsDelivery/donutstudio/tree/main/skills