Tonia — Music Theory Trainer

Tonia teaches you to hear intervals and chords, and explains the theory behind what you are hearing. Every note is generated on your device, so the pitch is exact and nothing is downloaded.

Everything runs offline. There is no account, no sign-up, no ads, and the app requests zero Android permissions.

WHAT YOU GET

• Ear training that adapts
Intervals, chords, scales and cadences. Tonia tracks which intervals you miss and brings them back more often. Play the two notes apart, together, or lower note first.

• The circle of fifths, interactive
Tap a key and the wheel rotates it to the top, showing its relative minor, its neighbors and its key signature. Open a key for its scale, its seven diatonic chords and a keyboard diagram.

• 96 chords
Triads, sevenths, suspended, diminished and half-diminished, each with its notes, its intervals in semitones, a keyboard diagram and all its inversions.

• 36 theory lessons in four tracks
Fundamentals, harmony, rhythm, and modes and scales — short, worked, and in plain English.

• Tuning you control
Set the reference pitch between 415 and 444 Hz, and switch between equal temperament and just intonation. Tonia shows you exactly how far apart they are in cents.

• Four instrument voices
Piano, sine, strings and organ — each a different stack of partials with its own envelope. Nothing is sampled, so the whole sound engine costs a few kilobytes.

• Eight background themes
A full Appearance section with eight crafted backgrounds and a modern, animated navigation bar.

PRIVACY FIRST
Tonia only plays sound. It never records, there is no microphone feature, and the manifest contains no permissions at all. Your progress stays in local storage on your device.

WHO IT IS FOR
Music students, self-taught players, singers working on pitch, and anyone who can play a piece but could not name the interval they just played.