Ninth

This article is about the musical interval. For the ordinal of 9, see 9. For the chord, see Ninth chord. For the curse, see Curse of the ninth. For the symphony, see Symphony No. 9 (Beethoven). For the 2011 albums, see Ninth (Peter Murphy album) and Ninth (The Gazette album).

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

major ninth

Inverse	minor seventh
Name
Other names	compound second
Abbreviation	M9
Size
Semitones	14
Cents
12-Tone equal temperament	1400.0

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

minor ninth

Inverse	major seventh
Name
Abbreviation	m9
Size
Semitones	13
Cents
12-Tone equal temperament	1300.0

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 D♭₅ (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:

Schumann, Faschingsschwank Intermezzo, bars 1–4

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

augmented ninth

Inverse	diminished seventh
Name
Abbreviation	A9
Size
Semitones	15
Cents
12-Tone equal temperament	1500.0

An augmented ninth is a compound musical interval spanning 15 semitones, or 3 semitones above an octave. For instance, the interval between C₄ and D♯₅ (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

References

1. Hamm, Chelsey; Hughes, Bryn (2026-02-01). "Intervals". VIVA.
2. Westergaard, Peter (1975). An Introduction to Tonal Theory, p.74. W.W. Norton. ISBN   978-0-393-09342-1.
3. McCormick, Scott (18 January 2019). "The Lush World of Eleventh Chords" . Retrieved 31 March 2019.