Perfect Unison

General info

Name

Perfect Unison

Quality

Perfect

Degree distance

1 degree

Semitones

0

Short description

Two sounds at exactly the same pitch. The foundation of any harmony — the root.

Interval structure

Lower note

Root (tonic)

Upper note

Same tone (doubling)

Degree formula

II0 stII

Semitone formula

0 semitones

Interval construction

Interval formula

P1

How it's built

Two notes are taken at the exact same pitch — no movement at all.

Brief explanation

Unison is the "zero" interval. It is essentially the same note played simultaneously or repeated. It serves as the foundation for building all other intervals.

How the interval sounds

Sound character

Unison sounds completely stable and neutral. There is no tension — it is a perfect pitch match. In an orchestra, doubling at unison reinforces the timbre. On guitar, unison means the same note on two different strings or a repeated note.

Consonance / dissonance

Explanation

Unison is a perfect consonance. Two sounds merge completely and are perceived as one. It is the most stable of all intervals because the vibration frequencies match perfectly.

Tendencies & resolutions

Behavior

Unison does not require resolution — it is already a point of absolute rest. Any movement from unison creates a new interval.

Harmonic context

Context

Unison is present in every chord as the root. In orchestration, unison doubling is used to increase volume and tonal density. In guitar arrangements, unison on two strings creates a characteristic sound (e.g., the intro to "Blackbird").

Interval inversion