The Microtuning Problem
MIDI was designed in 1983. It gives you 128 note numbers and a single pitch bend wheel. If you want to tune a note to something other than 12-TET, your options are limited — and they vary wildly between DAWs.
Method 1: Global Pitch Tables
Some synths let you load a .scl or .tun file that remaps all 128 MIDI notes to custom frequencies. This works for fixed alternate tunings (Pythagorean, meantone, Werkmeister) but not for dynamic tuning where the same note needs different frequencies in different chords.
Method 2: Per-Note Pitch Bend
Send a pitch bend message before each note-on. This is the most widely supported method — every DAW and synth understands MIDI pitch bend. The downside: it's a channel-wide message. For true polyphonic microtuning, you need one MIDI channel per note, which burns through your 16 channels fast.
Method 3: CLAP Note Expressions
The CLAP plugin format (used by Bitwig Studio and supported by Reaper) supports per-note expressions — individual tuning offsets for each note in a chord, on the same channel. This is the gold standard for microtuning. No channel limits, sub-cent accuracy, true polyphonic control.
Method 4: MTS-ESP
ODDSound's MTS-ESP protocol lets a "master" plugin broadcast tuning tables to any connected "client" synths in real time. It works across DAWs but requires synth developers to add MTS-ESP client support.
What Arbit Does
Arbit handles microtuning output automatically based on your DAW:
- Bitwig Studio: Full CLAP note expressions with transport sync. Every note gets its exact frequency. This is the best experience.
- Reaper: CLAP note expressions supported. Per-note accuracy.
- Ableton Live / FL Studio / Studio One: VST3 with per-note pitch bend fallback. Not as precise as note expressions but fully automatic — you don't configure anything.
- Standalone: Built-in synthesis engines receive exact frequencies directly. No MIDI translation needed.
The key difference: in Arbit, you never think about microtuning output. You create harmonic links between notes, and the plugin handles the translation to whatever your DAW supports. The tuning is the composition — not a post-processing step.