What is a Minor Ninth?

A minor ninth is a musical interval that spans thirteen semitones. It is essentially the distance of a minor second extended by an octave. For example, the interval between C and D♭ an octave higher is considered a minor ninth.

The minor ninth has a very tense and dissonant sound because the two notes are close in pitch but separated by an octave. When played together, the interval creates a strong sense of instability and friction. Because of this intense sound, composers and musicians often use minor ninths to create dramatic or emotional tension in music.

Minor ninth intervals commonly appear in jazz harmony, film scores, and modern classical compositions. They are often used in extended chords, such as dominant seventh chords with added tensions, to add color and complexity to the harmony. Despite its dissonant quality, the minor ninth plays an important role in expressive and modern musical writing.