Perfect unison
Perfect unison: C, 0 semitones; perfect consonance.
Octaves
Theory
General info
- Interval
- Perfect unison
- Quality
- Perfect
- Semitones
- 0
- Degree distance
- 1 degree
- Degree
- 1
Interval structure
- Lower note
- C (261.6 Hz)
- Degree formula
- II
- Semitone formula
- 0 semitones
Interval construction
- Interval formula
- P1
- Brief explanation
- A perfect unison joins two sounds at the same pitch and spans zero semitones. It may occur through unison doubling or repetition of one note.
Interval notes
1Croot
Consonance / dissonance
- Sonority
- Perfect consonance
- Explanation
- A perfect unison is a perfect consonance. Matching pitch creates no intervallic dissonance, although two sources may differ in timbre and loudness.
How the interval sounds
A unison joins two sounds at the same pitch and spans zero semitones. When sounded together, pitch remains the same while timbre and loudness may differ.
Famous example:
- Any held note — the root of a key
Tendencies & resolutions
A unison does not require resolution by itself. Moving either voice changes it into another interval whose function comes from harmonic context.
Interval inversion
- Inverts to
- Octave
- Quality change
- Perfectperfect
- Inversion rule
- When inverting unison, the upper note moves up an octave. Unison inverts to an octave: P1 → P8.
Related intervals
Close intervals
Appears in chords
CMajorCMinorCDominant 7CMajor 7CMinor 7CDiminishedCAugmentedCDiminished 7thCAugmented 7thCHalf-dim 7
Appears in scales & modes
How to play on piano
This interval on guitar 🎸
See how Perfect unison looks on guitar.