Giusto: Violin & Cello Tuner

Giusto is a tuner and metronome for string players. Presets cover violin (free), viola, cello and double bass (Pro), and the chromatic mode reads any pitch, so guitar, bass, ukulele, mandolin and banjo work too. Pro also adds just intonation and the other unequal temperaments.

The tuner
Pitch is estimated with three methods (YIN, probabilistic YIN, and MPM over the normalised square difference), which you can switch between in Settings. The reference A moves in 0.1 Hz steps, with quick settings from 415 Hz (baroque pitch) to 445 Hz, for playing with an ensemble that is not at 440.

24 instrument tunings across six families. Bowed strings: violin, viola, cello and double bass; the rest are guitars (standard, Drop D, DADGAD, open tunings, seven-string), basses (four, five and six strings), ukuleles (soprano, low G, baritone), mandolin and banjo. The violin tuner preset is free. Without Pro, you can still tune a cello or viola in automatic detection, which names any note and shows how many cents sharp or flat it is.

Ten temperaments, not just equal: just intonation in major and minor, Pythagorean, quarter-comma and sixth-comma meantone, and four unequal ones. In just intonation, thirds and fifths ring without beats. Every temperament except equal is tuned relative to a tonic you choose.

Eight transposing keys (A, B♭, B♭ bass, D, E♭, E♭ alto, F and G) next to concert pitch, so a B♭ clarinet or an E♭ alto sax reads at written pitch. Four ways of naming notes: letters, solfège, German H, and Japanese ハニホ.

In unit tests with synthesised tones, every error stayed within 1 cent; the largest reported was 0.32 cents, for harmonic tones. That measures the detection code, not your device's microphone or a room.

The metronome
Nine time signatures, and the compound ones carry their accent grouping: 5/8 as 3+2, 7/8 as 2+3+2, 9/8 as 3+3+3, 11/8 as 3+3+3+2, 12/8 as 3+3+3+3. Accents can also be set per beat by hand. Tempo runs from 30 to 300 BPM, with tap tempo. A one- or two-bar count-in is in Pro.

Ten subdivision settings, including straight eighths, triplets, sixteenths, swing, quintuplets, sextuplets, gallop and its reverse. Fifteen click sounds, from wood block and claves to hi-hat and marimba, so you can pick one that does not clash with your own instrument.

Two practice tools. The tempo trainer raises the tempo on its own every N bars. Bar muting silences whole bars at a time, so you can tell whether the pulse is in you or in the speaker. Timing is scheduled by sample position rather than by wall clock; over a simulated 30 minutes the scheduling error stays at 0.000001 samples (a scheduler unit-test figure, not a measurement of real audio output).

Practice time
Minutes played today and days in a row are counted while you tune or use the metronome. The streak is recounted from the days you actually practised, so a time-zone change does not break it, and late-night practice counts toward the previous day.

Free
The tuner has guitar standard, four-string bass, soprano ukulele and violin presets, automatic, string and piano detection, and equal temperament. The metronome has 2/4, 3/4, 4/4 and 6/8, four subdivisions and four click sounds. Practice time is included. No ads.

Pro
All 24 tunings, all six detection modes, all ten temperaments, all nine time signatures, all ten subdivisions, all fifteen click sounds, transposing instruments, the tempo trainer, bar muting, count-in and high-precision mode. Monthly, yearly and one-time purchase.

Languages
English, Japanese, German, Spanish, French, Italian, Korean, Portuguese, and Simplified and Traditional Chinese.

Recent changes:
Fixed the Back button closing the whole app on the Pro purchase screen. It now closes just that screen.