Intervals by ear

An interval is the distance between two notes, measured in semitones — the smallest step from one note to the very next one, black key or white.

Every pair of notes has its own flavor, but the pair that matters most for playing by ear is the major third against the minor third: four semitones sounds bright, three sounds dark, and telling them apart instantly is the difference between guessing at a melody and actually hearing it.

The fastest way to learn an interval is to anchor it to a song you already know by heart — any song, in any language, as long as you can hum its first two notes from memory. As illustrations of the method, not a list you have to use: the traditional song “Greensleeves” opens with a rising minor third, the standard “When the Saints Go Marching In” opens with a rising major third, and “Maria,” from West Side Story, opens with a rising tritone — the tense interval sitting exactly between a fourth and a fifth. If none of those three come to mind, pick a song that does; the technique works the same way. Once an interval has a song attached to it, you stop counting semitones and start recognizing a sound.

Intervals also come in two shapes. Melodic means the two notes play one after another, like a tune. Harmonic means they play together at once, like a chord made of only two notes. Both describe the exact same distance — your ear just hears it differently depending on whether the notes overlap.

The exercise below plays two notes and asks you to name the gap between them. Answer wrong, and it tells you the interval you actually heard.