Ninth

In music, a ninth is a compound interval consisting of an octave plus a second.

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.^[1]

A major ninth is a compound musical interval spanning 14 semitones, or an octave plus 2 semitones. If transposed into a single octave, it becomes a major second or minor seventh. The major ninth is somewhat dissonant in sound.

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.

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). If transposed into a single octave, it becomes a minor second or major seventh. The minor ninth is rather dissonant in sound,^[2] and in European classical music, often appears as a suspension. Béla Bartók wrote a study in minor 9ths for piano. 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:

^{[citation needed]} Alexander Scriabin's Piano Sonata No. 9, 'Black Mass' is based around the interval of a minor ninth, creating an uncomfortable and harsh sound.^{[citation needed]} Several of Igor Stravinsky's works open with a striking gesture that includes the interval of a minor 9th, either as a chord: Les Noces (1923) and Threni (1958); or as an upward melodic leap: Capriccio for Piano and Orchestra (1929), Symphony in Three Movements (1946), and Movements for Piano and Orchestra (1960).

An augmented ninth is a compound musical interval spanning 15 semitones, or 3 semitones above an octave. Enharmonically equivalent to a compound minor third, if transposed into a single octave, it becomes a minor third or major sixth.

See: Dominant seventh sharp ninth chord.

Three types of ninth chords may be distinguished: dominant (9), major (M9), and minor (m9).^[3][4] They may easily be remembered as the chord quality of the seventh does not change with the addition of the second scale degree,^[3] which is a major second in both major and minor, thus:

0 4 7 t + 2 = dominant seventh + ninth = dominant ninth chord
0 4 7 e + 2 = major seventh + ninth = major ninth chord
0 3 7 t + 2 = minor seventh + ninth = minor ninth chord

The dominant ninth (V₉) is a dominant seventh plus a major or minor ninth.^[5]

• Augmented octave
• Augmented unison

This page was last edited on 4 February 2023, at 14:32