# HarmoTuner: Chord Tuner — 4-Note Just Intonation

> 4-Note Just Intonation (iPhone/iPad app by Shunsuke Hosomi.)

- Source: https://appshunter.io/ios/app/harmotuner-chord-tuner/id6780727272 (this page in markdown: same URL + `.md`)
- Developer: [Shunsuke Hosomi](https://appshunter.io/developer/6780727274)
- Category: Music, Utilities
- Price: Free
- Age rating: 4+
- Requires: iOS 17.0 · 1 MB
- Languages: American English, Japanese
- Released: 2026-06-16
- Data updated: 2026-10-24

## What is HarmoTuner?

HarmoTuner is a tuner and metronome designed to help ensembles explore harmony through just intonation.

Alongside precise single-note tuning, HarmoTuner lets you choose a target chord and compare the current position of each chord tone with its just-intonation target. Use it for individual long-tone practice or for shaping intonation and resonance in wind bands, orchestras, chamber groups, and other ensembles.

CHORD TUNING

Choose a target from 96 chords, including C, Am, G7, and CM7.

HarmoTuner detects up to four input tones and displays a separate gauge for each role in the chord, such as the root, third, fifth, and seventh. In addition to the deviation from equal temperament, a target marker shows where each tone sits in just intonation.

You can also find possible chords by selecting the note names you hear, making it easy to choose a target even when you do not know the chord symbol.

SINGLE-NOTE TUNER

View the note name, frequency, and deviation in cents from the selected reference in real time.

• Adjustable A4 reference pitch
• Equal temperament, just intonation, Pythagorean tuning, and meantone temperament
• Adjustable input sensitivity and lock sensitivity
• Lock indicator for a stable pitch
• Reference tone with selectable note and octave
• Analysis display for waveform and harmonic content

Use it not only for tuning an instrument, but also for long tones and for checking the stability of embouchure and breath support.

METRONOME

Set the tempo, meter, and subdivision, then follow the beat through sound and visual feedback.

• 30–300 BPM
• Meters from 1/4 to 10/4
• Quarter-note, eighth-note, triplet, and sixteenth-note subdivisions
• Tap tempo
• Tempo marking display
• Optional screen-edge beat flash

Practice intonation and tempo without switching between apps.

THREE FOCUSED MODES

Open Tuner, Chord, or Metronome directly from its own tab. HarmoTuner remembers your most recently used mode and settings, so you can get back to practice quickly.

PRIVACY

All microphone input is analyzed on your device. HarmoTuner does not save recordings, transmit audio to external servers, or collect personal information.

## Is HarmoTuner safe?

Not enough ratings yet to assess HarmoTuner.

## Is HarmoTuner legit?

HarmoTuner: Chord Tuner has limited verification signals. The AppsHunter Legitimacy Score for HarmoTuner is 58 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 4 releases)

### 1.3 — 2026-10-24

The metronome now has Tap Tempo. When you don't know a piece's tempo, just tap along with the beat a few times and the BPM follows.

- Tap Tempo: estimates BPM from the rhythm you tap
- The metronome now keeps playing while the screen is locked or the app is in the background (the microphone and reference tone stop, to protect your privacy)
- When audio stops because of a phone call or unplugged headphones, the app now tells you on screen and lets you resume with one tap
- The metronome and reference tone are now as loud as other apps
- The tuner, the metronome and the reference tone now run one at a time: starting one stops the others (this is what makes the louder playback possible without clipping, and keeps the microphone from hearing the speaker)
- Chord tuning is far more precise: each chord tone is measured to within ±2 cents, including voicings stacked over a bass note
- Fixed the meantone targets for the minor third and minor seventh
- iPhone is now portrait-only; added VoiceOver labels
- Text now follows the iOS text-size setting, and caption colours were raised to a readable contrast
- More robust restoration of saved settings, plus general stability improvements

### 1.2 — 2026-07-12

• Reorganized the app into three tabs: Tuner, Chord, and Metronome
• Made chord tuning quicker and easier to access
• Improved the target chord display for better readability
• Improved audio analysis performance and metronome stability

### 1.1 — 2026-06-18

• - Improved single-note detection stability
  - Improved chord detection accuracy
  - Reduced brief pitch display jumps
  - Adjusted input sensitivity and noise tolerance
  - Made just intonation status easier to understand
  - Updated the app icon to reflect a just-intonation Cmaj7 layout

### 1.0 — 2026-06-17

No release notes.

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-24.*