Definition
A ninth chord adds the 9th (that is, the 2nd an octave higher) to a seventh chord. The 9th is the first tension of the stack of thirds: 1 – 3 – 5 – 7 – 9. When the seventh is missing we speak of add9 (a triad with an added 9th).
The qualities on C
| Symbol | Notes | Base chord | Color |
|---|---|---|---|
| Cmaj9 | C E G B D | Cmaj7 + 9 | bright, open, neo-soul |
| C9 | C E G Bb D | C7 + 9 | funk, blues, “soft” dominant |
| Cm9 | C Eb G Bb D | Cm7 + 9 | soft, R&B, lo-fi |
| C7b9 | C E G Bb Db | C7 + minor 9th | tense dominant, toward a minor tonic |
| C7#9 | C E G Bb D# | C7 + augmented 9th | “Hendrix chord”, blues-rock, funk |
| Cm(maj9) | C Eb G B D | Cm(maj7) + 9 | dark, cinematic (“Bond” chord) |
| C9sus4 | C F G Bb D | C7sus4 + 9 | suspended, gospel and modal jazz |
| Cadd9 | C E G D | triad + 9 (no 7th) | pop, acoustic rock |
| Cm(add9) | C Eb G D | minor triad + 9 | melancholic, pop |
| C6/9 | C E G A D | triad + 6 + 9 | see the card on sixth chords |
Where they occur diatonically (C major)
| Degree | Chord | Ninth |
|---|---|---|
| I | Cmaj9 | D (natural 9) |
| ii | Dm9 | E (natural 9) |
| iii | Em7(b9) | F (b9: avoided as a tension) |
| IV | Fmaj9 | G |
| V | G9 | A |
| vi | Am9 | B |
| vii | Bø7(b9) | C (b9: avoided) |
Berklee rule: the available tensions are those a tone above a chord note; a minor 9th above the root (iii and vii) is considered an “avoid” note on non-dominant chords. On the dominant, however, b9 and #9 are typical altered tensions, especially when resolving to a minor tonic (G7b9 → Cm).
The ninth in classical theory
In common practice the dominant ninth (V9: G B D F A in C major; G B D F Ab in C minor) appears in Beethoven, Chopin, Wagner. It is often treated as an appoggiatura or suspension over the V7, and the minor V9 without the root coincides with the vii°7 (B D F Ab). Rameau considered the ninth a chord by “supposition” (a third added below the bass).
Voicing
- Drop the fifth: it is the least important note. Cmaj9 in 4 voices: C (bass) – E – B – D.
- Rootless voicings (Bill Evans, Wynton Kelly): the bassist plays the root and the piano plays 3–5–7–9 or 7–9–3–5. Dm9 = F A C E (3 5 7 9); rootless G9 = B D F A (3 5 7 9) or F A B D (7 9 3 5).
- Register: the 9th must sit above the 3rd and the 7th; a minor 9th below about E2 becomes mud (see the low interval limit).
- Guitar: the C9 shape with the root on the 5th string (x32333) is the funk voicing par excellence; E9 at the 7th fret (x7677x) is the basis of James Brown's “chicken scratch”.
Examples in real songs
- James Brown, “Sex Machine” and many funk tracks: the rhythm guitar plays ninth chords (E9) in short sixteenth-note hits.
- “Purple Haze” (Jimi Hendrix) and “Taxman” (The Beatles): the seventh chord with #9 as the main color.
- “What's Going On” (Marvin Gaye): the maj7 – m7 vamp is often played with added ninths, the foundation of the soul and neo-soul sound.
- Neo-soul (D'Angelo, Erykah Badu) and lo-fi hip hop: chains of m9 and maj9 on Rhodes (Stage-73 V) with rootless voicings.
Exercise
- Play Dm9 – G13 – Cmaj9 with rootless voicings (F A C E – F A B E – E G B D) on a Rhodes: you have the “jazz pianist's” ii–V–I.
- Compare G7 → Cm with G7b9 → Cm: hear how the Ab prepares the minor color.
- Program a James Brown-style funk groove on guitar (or a synth pluck) on E9, with sixteenth-note hits and ghost notes.
Related topics
Simple and compound intervals; Extensions and tensions (9, 11, 13); Altered chords; Voicing: close, open, drop 2, shell; Upper structure triads.