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.[1]
Heinrich Schenker and also Nikolai Rimsky-Korsakov allowed the substitution of the dominant seventh, leading-tone, and leading tone half-diminished seventh chords, but rejected the concept of a ninth chord on the basis that only that on the fifth scale degree (V9) was admitted and that inversion was not allowed of the ninth chord.[2] [3]
| Chord Name: | Dominant ninth |
| First Interval: | root |
| Second Interval: | major third |
| Third Interval: | perfect fifth |
| Fourth Interval: | minor seventh |
| Fifth Interval: | major ninth |
| Tuning: | 4:5:6:7:9 |
| Forte Number: | 5-34 |
| Complement: | 7-34 |
A dominant ninth chord is a dominant seventh chord plus a major ninth above the root. For instance, a C dominant ninth chord (C9) consists of the notes C–E–G–B–D.
When the symbol "9" is not preceded by the word "major" or "maj" (e.g., C9), the chord is a dominant ninth. 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.[4]
In the common practice period, "the root, 3rd, 7th, and 9th are the most common factors present in the V9 chord," with the 5th, "typically omitted".[5] The ninth and seventh usually resolve downward to the fifth and third of I.
Example of tonic dominant ninth chords include Bobbie Gentry's "Ode to Billie Joe" and Wild Cherry's "Play That Funky Music". James Brown's "I Got You (I Feel Good)" features a striking dominant 9th arpeggio played staccato at the end of the opening 12-bar sequence. The opening phrase of Chopin's well-known "Minute Waltz" climaxes on a dominant 9th chord:
César Franck's Violin Sonata in A major opens with a dominant ninth chord (E9) in the piano part. When the violin enters in the fifth bar, its melody articulates an arpeggio of this chord.
Debussy's "Hommage a Rameau", the second of his first Book of Images for piano solo climaxes powerfully on a dominant ninth, expressed both as a chord and as a wide-ranging arpeggio:
The starting point of Karlheinz Stockhausen's piece for vocal sextet, Stimmung (1968) is a chord consisting of the notes B, F, B, D, A and C.[6] According to Nicholas Cook,[7] Stimmung could, in terms of conventional tonal harmony, be viewed as "simply a dominant ninth chord that is subject to timbral variation. The notes the performers sing are harmonics 2, 3, 4, 5, 7, and 9 of the implied but absent fundamental—the B flat below the bass clef."
| Chord Name: | Dominant minor ninth |
| First Interval: | root |
| Second Interval: | major third |
| Third Interval: | perfect fifth |
| Fourth Interval: | minor seventh |
| Fifth Interval: | minor ninth |
| Tuning: | 8:10:12:14:17 |
| Forte Number: | 5-31 |
| Complement: | 7-31 |
A dominant minor ninth chord consists of a dominant seventh chord and a minor ninth above the root. For instance, a C dominant minor ninth chord (C79) consists of the notes C–E–G–B–D.
Fétis tuned the chord 8:10:12:14:17.
In Schubert's Erlkönig, a terrified child calls out to his father when he sees an apparition of the sinister Elf King. The dissonant voicing of the dominant minor ninth chord used here (C79) is particularly effective in heightening the drama and sense of threat.
(Excerpt from Schubert's Erlkönig – Link to passage)
Writing about this passage, Taruskin (2010, p. 149) remarks on the
| Chord Name: | Minor ninth |
| First Interval: | root |
| Second Interval: | minor third |
| Third Interval: | perfect fifth |
| Fourth Interval: | minor seventh |
| Fifth Interval: | major ninth |
| Tuning: | 20:24:30:36:45 |
| Forte Number: | 5-27 |
| Complement: | 7-27 |
The minor ninth chord consists of a minor seventh chord and a major ninth above the root. For instance, a C minor ninth chord (Cm9) consists of the notes C–E–G–B–D.
| Chord Name: | Major ninth |
| First Interval: | root |
| Second Interval: | major third |
| Third Interval: | perfect fifth |
| Fourth Interval: | major seventh |
| Fifth Interval: | major ninth |
| Tuning: | 8:10:12:15:18 |
| Forte Number: | 5-27 |
| Complement: | 7-27 |
A major ninth chord (e.g., Cmaj9), as an extended chord, adds the major seventh along with the ninth to the major triad. For instance, a C major ninth chord (Cmaj9) consists of the notes C–E–G–B–D.
See main article: Dominant seventh sharp ninth chord.
| Chord Name: | Dominant seventh sharp ninth chord |
| First Interval: | root |
| Second Interval: | major third |
| Third Interval: | perfect fifth |
| Fourth Interval: | minor seventh |
| Fifth Interval: | augmented ninth |
| Tuning: | 160:200:240:288:375 |
| Forte Number: | 5-32 |
| Complement: | 7-32 |
A dominant seventh sharp ninth chord is a dominant seventh chord plus an augmented ninth above the root. For instance, a C dominant seventh sharp ninth chord (C79) consists of the notes C–E–G–B–D.
The 6/9 chord is a pentad with a major triad joined by a sixth and ninth above the root, but no seventh. For example, C6/9 is C–E–G–A–D. It is not a tense chord requiring resolution, and is considered a substitute for the tonic in jazz. The minor 6/9 chord is a minor triad with an added 6th and 9th, evoking the Dorian mode, and is also suitable as a minor tonic in jazz.[8]
The second degree is octave equivalent to the ninth. The ninth chord could be alternatively notated as seventh added second chord (C7add2), from where omitting the 3rd produces the seventh suspended second chord (C7sus2).
An add9 chord, or added ninth chord, is any chord with an added ninth – Cadd9 consists of C, E, G and D, Cmadd9 consists of C, E flat, G, and D, Cdimadd9 consists of C, E flat, G flat, and D, etc. Added ninth chords differ from other ninth chords because the seventh is not necessarily included. An add9 can also be added to an interval, like a C5, resulting in a C5add9 chord which consists of C and G (C5) with D as an added 9 (C, G, D). Note that if the note is within an octave from the root, it is a second, not a ninth. In the case of C, D, G, within a fifth rather than spanning a ninth, this is a Csus2 chord, where the second, D, replaces the third, E (C, D, G instead of C, E, G).
