Unison

0 semitones — two notes at the same pitch

Degree 1Solfège: doNotation: P1

The unison is two notes at the same pitch — an interval of 0 semitones, also called the prime. It is perfectly consonant: the most stable relationship possible, since the two notes are identical. More a reference point than an interval in practice, it is the root from which all others are measured.

The instrumentTap a note to hear it.

One frequency, and no harmonics

Harmonic seriesEach row is one harmonic of the note — n times the fundamental's frequency, about 1/n of its strength — faster and fainter as it climbs. The rows in ink are where the chosen interval first arises. The bottom row is the one your ear actually receives: those rows added, a single wave. The shaded band is one repeat of it — the shorter that pattern, the sooner the ear settles on it as one sound. Harmonic 1 alone — the fundamental, a pure tone at f. Pick an interval above to see where it first appears.

Contained byIntervalsRelatedSolfège Root Consonance