Ninth chord

In music theory, a ninth chord is a chord that encompasses the interval of a ninth when arranged in close position with the root in the bass.

Dominant ninth

There is a difference between a Major Ninth chord and a Dominant Ninth chord. A dominant ninth is a dominant chord (and minor 7th) with a ninth. A major ninth chord (e.g., Cmaj9), as an extended chord, adds the major seventh along with the ninth to the major triad. Thus, a Cmaj9 consists of C E G B and D  play . When the symbol "9" is not preceded by the word "major" or "maj" (e.g., C9), the chord is a Dominant 9th. That is, the implied seventh chord is a dominant seventh, i.e. a major triad plus the minor seventh, to which the ninth is add: e.g., a C9 consists of C E G B♭ and D  play . C Dominant Ninth (C9) would usually be expected to resolve to an F major chord (the implied key, C being the dominant of F). The ninth is commonly chromatically altered by half-step either up or down to create more tension and dissonance. Fétis tuned the chord 4:5:6:7:9.

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.

Major ninth

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.

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). If transposed into a single octave, it becomes a minor second or major seventh. The minor ninth is rather dissonant in sound, 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 a constructed to feature prominent notes of the melody a minor ninth above the accompaniment: