insTuner vs JustATuner

insTuner is a chromatic tuner for instruments including guitar, bass, piano, bowed strings, brass, woodwinds and drums. It offers five modes: Instant Tuning, Fine-Tuning, Strobe Tuning, Spectrum (FFT) and Spectrogram. The note wheel identifies the note being heard and shows its octave beneath the dial. Fine-Tuning displays the note, cent deviation and frequency; Spectrum analyzes frequencies and allows a logarithmic or linear X-axis. A built-in tone generator produces four waveforms for tuning by ear. The free edition includes Instant-Tuning Mode and the tone generator. The paid plan is listed at $3.99 as a one-time purchase and includes the Mac app, fine-tuning, historical curve tuning, tone generation and tuning settings. Those settings include Concert A frequency, musical temperament and input source. The Mac listing requires macOS 10.9 or later. The maker says the paid app can be bought once for use on iPhone, iPad and iPod Touch. EUMLab says it was founded in 2012 and is based in Hangzhou, China and Berlin, Germany.

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.