Ninth Explained

In music, a ninth is a compound interval consisting of an octave plus a second.^[1] Like the second, the interval of a ninth is classified as a dissonance in common practice tonality. Since a ninth is an octave larger than a second, its sonority level is considered less dense.^[2]

Major ninth

A major ninth is a compound musical interval spanning 14 semitones, or an octave plus 2 semitones. For instance, the interval between C₄ and D₅ (in scientific pitch notation) is a major ninth.

If transposed into a single octave, it becomes a major second or minor seventh. The major ninth is somewhat dissonant in sound.

Transposition

Some common transposing instruments sound a major ninth lower than written.These include the tenor saxophone, the bass clarinet, the baritone/euphonium when written in treble clef, and the trombone when written in treble clef (British brass band music).

When baritone/euphonium or trombone parts are written in bass clef or tenor clef they sound as written.

Minor ninth

A minor ninth (m9 or -9) is a compound musical interval spanning 13 semitones, or 1 semitone above an octave (thus it is enharmonically equivalent to an augmented octave). For instance, the interval between C₄ and D₅ (in scientific pitch notation) is a minor ninth.

If transposed into a single octave, it becomes a minor second or major seventh. The minor ninth is rather dissonant in sound,^[3] and in European classical music, often appears as a suspension.

The fourth movement (an intermezzo) of Robert Schumann's Faschingsschwank aus Wien is constructed to feature prominent notes of the melody a minor ninth above the accompaniment:

Béla Bartók wrote a study in minor ninths for piano. Several of Igor Stravinsky's works open with a striking gesture that includes the interval of a minor 9th, either as a chord, as in Les noces and Threni, or as an upward melodic leap, as a in Capriccio for Piano and Orchestra, Symphony in Three Movements, and Movements for Piano and Orchestra.

Augmented ninth

An augmented ninth is a compound musical interval spanning 15 semitones, or 3 semitones above an octave. For instance, the interval between C₄ and D₅ (in scientific pitch notation) is a major ninth.

Enharmonically equivalent to a compound minor third, if transposed into a single octave, it becomes a minor third or major sixth.

See also

• Augmented octave
• Augmented unison

Notes and References

1. Web site: Intervals. Hamm. Chelsey. Hughes. Bryn. 2026-02-01. VIVA.
2. [Peter Westergaard|Westergaard, Peter]
3. Web site: McCormick . Scott . The Lush World of Eleventh Chords . 18 January 2019 . 31 March 2019.