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SPECIFICTION
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JustATuner

stohrermusic.com

Free plan WindowsmacOSLinux
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Spec score 7.7 #17 of 32 in Musical Tuner Apps

What it is

JustATuner is a free, open-source desktop tuner for musicians, combining a stroboscopic tuner with a just-intonation drone. Its chromatic tuner has 12 wheels for the pitch classes, each with seven concentric rings. Users can set reference pitch and instrument transposition, and adjust cents bias for each wheel and octave bias for each ring. The drone plays root, root-plus-fifth, major-triad, or minor-triad voicings in a pure sine or harmonic-stack sound. A live meter reports the just-intonation interval and cents difference, marking LOCKED within 5¢ of just intonation. A Lissajous display shows interference between the played note and drone, with adjustable color, trace thickness, trail count, and resolution. The app detects pitch through a microphone; its maker recommends a quality microphone and strongly recommends headphones while the drone is on. It is available for Windows, Linux, and macOS on Apple Silicon M1, M2, M3, and M4. Linux requires PortAudio, and the downloaded binary may need executable permission. The maker says the app is unsigned, so an operating-system warning may appear.

Spec sheet

Product
JustATuner is a free, open-source desktop tuner for musicians with a stroboscopic tuner and a just-intonation drone.Read 2 Oct 2026 · stohrermusic.com
Support
The maker lists [email protected] for questions or feedback.Read 2 Oct 2026 · github.com
Maker
The software page identifies Matt Stohrer as the maker; his About page says he moved to North Carolina in 2010 and lives between Durham and Hillsborough.Read 2 Oct 2026 · stohrermusic.com
Downloads and signing
Downloads are hosted on GitHub, and the maker says the app is not signed with a developer certificate, so the operating system may show a warning.Read 2 Oct 2026 · stohrermusic.com
Drone practice
The drone supports root, root-plus-fifth, major-triad, and minor-triad voicings, with a pure sine or harmonic-stack sound.Read 2 Oct 2026 · stohrermusic.com
Instrument support
Transposition options include Concert, B♭, E♭, and F, and pitch-detection presets cover saxophones, voice, brass, and strings.Read 2 Oct 2026 · stohrermusic.com
Interval analysis
A live meter reports the just-intonation interval and cents difference, and marks LOCKED within 5¢ of just intonation.Read 2 Oct 2026 · stohrermusic.com
Linux requirement
Linux use requires PortAudio, and the downloaded binary may need its executable permission set.Read 2 Oct 2026 · stohrermusic.com
Microphone and headphones
The app listens to a microphone for pitch detection; the maker recommends a quality microphone and strongly recommends headphones when the drone is on.Read 2 Oct 2026 · stohrermusic.com
Pitch settings
Users can configure reference pitch, instrument transposition, per-wheel cents bias, and per-ring octave bias.Read 2 Oct 2026 · stohrermusic.com
Source code
The source code is available on GitHub for inspection.Read 2 Oct 2026 · stohrermusic.com
Stroboscopic tuner
Its chromatic tuner has 12 wheels, one for each pitch class, with seven concentric rings per wheel.Read 2 Oct 2026 · stohrermusic.com
Supported systems
The maker lists Windows, macOS on Apple Silicon, and Linux; the macOS app is for M1, M2, M3, and M4 chips.Read 2 Oct 2026 · stohrermusic.com
Visualizer
The drone’s Lissajous display visualizes interference between the played note and drone, with configurable phosphor color, trace thickness, trail count, and resolution.Read 2 Oct 2026 · stohrermusic.com

Plans and prices

Free Free Desktop tuner and just-intonation drone · open source Read 2 Oct 2026 · stohrermusic.com

Every JustATuner plan and price →

Strong points and limits

Strong points

  • Free and open source.
  • Drone offers four voicing options.
  • Live meter reports interval and cents difference.
  • Instrument transposition presets include Concert, B♭, E♭, and F.

Limits

  • Linux use requires PortAudio.
  • Linux binary may need executable permission.
  • Unsigned downloads may trigger an operating-system warning.
  • Maker recommends headphones when the drone is on.

Who it suits

JustATuner suits musicians who want a desktop tuner with just-intonation drone practice and configurable pitch settings. It is available for Windows, Linux, and Apple Silicon Macs.

Verdict

JustATuner pairs a detailed stroboscopic display with a configurable just-intonation drone. Check the Linux requirement or unsigned-download warning for your system before setup.

Where Specifiction places it

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