Microtonal pitch correction moves a performance toward targets that are not restricted to the twelve equal-tempered semitones in an octave.
The difficulty is not adding more notes. It is deciding which pitches are structural, which change depending on harmony or melodic context, and which deviations are expressive rather than wrong. A tuner has no way to tell those apart, so you have to.
Quick answer: you need per-note cent offsets, an adjustable reference pitch, the ability to disable unused notes, and gentle correction settings. Build the target map from the actual recording rather than from a chart, and automate it where the music modulates.
Terms that prevent mistakes
12-TET. Twelve equal divisions of the octave, 100 cents per semitone. The piano, and the assumption baked into almost every pitch corrector.
Cent. One hundredth of an equal-tempered semitone. A unit of measurement, not a musical rule. Roughly 5 cents is where most listeners begin to notice on a sustained tone.
Just intonation. Intervals derived from simple frequency ratios, such as a 5:4 major third. The best target depends on the harmonic context, which is what makes it hard to automate.
Pythagorean tuning. Built primarily from pure 3:2 fifths, producing thirds noticeably different from 12-TET.
EDO. Equal divisions of the octave. 19-EDO and 24-EDO are the common ones in production contexts.
Scala and MTS-ESP. Two common ways software exchanges tuning definitions. Support varies enormously by plugin, and most vocal tuners do not have it, including NEOTUNE Pro. Check before you plan a workflow around it.
What a capable tuner needs
| Capability | Why it matters |
|---|---|
| Per-note cent offsets | Places targets between the piano keys at all |
| Adjustable reference pitch | Matches ensembles not recorded at A=440 |
| Custom note enable and disable | Stops the tuner being attracted to irrelevant targets |
| Smooth transition and Flex | Preserves bends and ornaments |
| Automatable target sets | Handles modulation and context-dependent tuning |
| A clear pitch readout | Lets you compare input, target and result |
That last one is underrated. Without a readout showing the detected note, the cents deviation and whether tracking is locked, you are guessing about whether a problem is detection or correction.
NEOTUNE Pro has an adjustable reference pitch from 430 to 450 Hz, per-note cent offsets of up to +/-100 on its keyboard, 37 scales of which 21 are microtonal or non-Western, Correction, Note Transition, Flex and Humanise as separate controls, and a live readout of note, cents, frequency and tracking state. It does not import Scala or MTS-ESP tuning files. See NEOTUNE Pro
Workflow 1: a fixed microtonal scale
The straightforward case, and the one that works best.
- Get the scale’s cent map from a musical source you trust, not a random chart.
- Set the reference pitch to the recording.
- Enter each allowed pitch class with its offset.
- Disable every note the music does not use.
- Test with slow correction on stable, sustained tones first.
- Only then audition the ornaments and transitions.
This works well when the scale has consistent octave-repeating targets. It starts breaking down as soon as the tuning is context-dependent.
Workflow 2: just intonation
Just intervals depend on the harmonic root, and that is the whole problem.
An E tuned as a 5:4 major third above C is not the same E you want as a fifth above A. A static twelve-key offset map physically cannot express both, because it has one slot for E.
Three ways around it, in order of practicality:
- Automate the offsets by chord. Tedious but exact.
- Drive targets from MIDI, so the chord determines the target.
- Correct only obvious drift and let the ensemble define the pitch, which is what most good recordings of this music do anyway.
Workflow 3: gamelan and other ensemble-specific tunings
“Gamelan tuning” is not one universal cent table, and treating it as one is the mistake worth warning about.
Individual ensembles have their own slendro and pelog tunings. Paired instruments are frequently tuned slightly apart on purpose so that the beating between them is part of the sound.
Measure the actual reference instrument from the recording, or leave the vocal flexible and correct nothing. Do not normalise it to a generic preset found online and describe the result as authentic.
The same caution applies to any tradition with living regional practice, which is covered for Arabic music in maqam and autotune.
When not to correct
The most important section here.
Do not correct a blue note, a maqam inflection, a raga ornament, a barbershop adjustment, a fretless slide or a deliberate ensemble beat pattern merely because a tuner display labels it sharp or flat. The display is measuring against 12-TET, and 12-TET is the thing the music is not doing.
Ask first whether the movement is structural to the style. Correction is for a performer missing a target they intended to hit. It is not for a measurement system misunderstanding the music.
How to build a custom target map
- Choose the reference frequency and the tonic.
- Write each target either as absolute cents from the tonic or as an offset from its nearest 12-TET note. Pick one convention and stay with it.
- Check octave equivalence. Some systems are not simple octave-repeating scales, and a per-pitch-class tuner cannot represent those at all.
- Enter only the targets the plugin can actually represent.
- Record a calibration tone, or use a trusted instrument from the session.
- Compare three things: the plugin’s meter, an independent spectral tuner, and a musician’s judgement. When they disagree, the musician wins.
- Save the preset with the reference frequency, the source, the date and the musical context in its name or notes. You will not remember in six months.
The limits of twelve offset keys
Per-pitch-class offsets are powerful and they are not unlimited. Be clear about where they stop, because plugins rarely are.
They cannot hold two differently tuned versions of the same pitch class at once. One slot per letter name.
They cannot retune a degree automatically per chord root. Adaptive just intonation needs something that knows the harmony.
They cannot represent more than twelve pitch classes per octave. 19-EDO and 31-EDO are out of reach.
They cannot represent non-octave scales such as Bohlen-Pierce.
If the work genuinely needs any of those, or needs polyphonic correction, use a system designed for it rather than forcing a vocal tuner to approximate.
Common failures
The result sounds Western. The offsets are not entered, or the tuner is on a major or minor preset. Build a custom scale.
It works in one section and not another. The music modulates. Automate the target set.
Everything fights the tuner. The recording is not at A=440. Set the reference pitch.
The ornaments are gone. Correction too fast and Flex too low. In this repertoire the ornaments are usually the point.
Chromatic did not help. Chromatic allows all twelve equal-tempered notes and none of the microtonal ones. It rounds less far, but it still rounds.
The readout disagrees with your ears. The readout is measuring against 12-TET. Trust the ears, then work out what the number should be.
Frequently asked questions
What is microtonal pitch correction? Correcting a performance toward pitch targets that are not limited to the twelve equal-tempered semitones, using per-note cent offsets or alternative tuning tables.
Is 24-TET the same as quarter-tone music? No. 24-TET is one particular equal-tempered 50-cent grid. Many traditions described as using quarter tones actually use variable neutral intervals that are not fixed at those positions.
Can a normal autotune plugin do microtonal correction? Only if it supports custom cent targets, alternative tuning tables or suitable MIDI control. A major and minor menu cannot do it at all.
What plugin does microtonal pitch correction? Any with per-note cent offsets. NEOTUNE Pro has 37 scales, 21 microtonal or non-Western, plus a custom scale with +/-100 cent offsets per pitch class and a 430-450 Hz reference pitch.
Can pitch correction process chords? Most real-time vocal tuners expect monophonic input. Chords and doubled voices confuse fundamental tracking, and microtonal work makes that worse because the targets are closer together.
How many cents is noticeable? Around 5 cents on a sustained tone for most listeners, less on a pure sustained interval where beating gives it away, considerably more during fast passages.
Does NEOTUNE Pro import Scala or MTS-ESP files? No. It has 37 built-in scales and a custom scale with per-note cent offsets, but it does not read external tuning files.
Should I correct traditional music at all? Often barely. Stabilise accidental drift and leave the intonation, the ornaments and the ensemble relationships alone unless a specific fusion sound is the goal.
NEOTUNE Pro has 37 scales with 21 microtonal or non-Western options, a custom scale with +/-100 cent offsets on every pitch class, a 430-450 Hz reference and a live note, cents and tracking readout. $29.99. See the plugin.
Related: maqam and autotune and why does autotune sound warbly.
Also: retune speed explained, because gentle correction matters more here than anywhere else.
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