Perfect unison

In music theory, unison is a special interval because it is a null interval: Two music notes with the same pitch form a unison.

What does unison look like?

Here is an example of a melodic unison (two notes of a melody) and a harmonic unison (two notes in a chord):

Unison quality

Unison can only be perfect, it cannot be major, minor, diminished, augmented, (and so on...) because by definition unison represents an interval formed by two notes of the same pitch .

Inversion of the perfect unison

The inversion of the perfect unison is the perfect octave.

Here is an example of a perfect octave:

Musical examples of perfect unison

Beethoven's Moonlight Sonata

After the introduction composed of arpeggios, the Beethoven's Moonlight Sonata begins with a succession of unison:

Interval identification game

You will find this interval in my Intervals identification game: