C7#9 C dominant seventh sharp nine chord
- Notes
- C E G Bb D#
- Formula
- 1 3 5 b7 #9
- Semitones
- 0 4 7 10 15 above the root
- Other symbols
- C7(#9), C7+9
C to E is a major third (4 semitones), E to G is a minor third (3 semitones), G to Bb is a minor third (3 semitones), Bb to D# is a perfect fourth (5 semitones). A dominant seventh with a raised ninth, D#. On the keyboard D# is the same key as the minor third, so the chord holds both a major and a minor third; it is written as a sharp ninth because it sits above the seventh and the letter names follow the stack of thirds.
C7#9 on the piano
Root position from C4: C4, E4, G4, Bb4, D#5. Middle C is C4.
C7#9 on the guitar
Standard tuning (E A D G B E). Strings run low E on the left to high e on the right, frets downwards; × is a muted string, ○ an open string, and each dot shows the note it sounds, with the root in blue-green. Every shape below has C as its lowest note.
x 3 2 3 4 x (low E to high e)
Sounds C3 E3 Bb3 D#4, fifth left out
The E-shape and A-shape grips are movable: an E-shape chord's root is the note under your first finger on the low E string, an A-shape chord's root is the note on the A string. Slide the same grip up or down to play dominant seventh sharp nine chords on other roots.
Inversions of C7#9
An inversion puts a note other than the root in the bass. The name is what semicord's chord finder calls those notes played bottom to top; a slash name like C/E means a C chord with E in the bass.
| Position | Notes, bass first | Named | Listen |
|---|---|---|---|
| Root position | C E G Bb D# | C7#9 | |
| 1st inversion | E G Bb D# C | Cm7/E (also read as C7#9/E) | |
| 2nd inversion | G Bb D# C E | C7#9/G | |
| 3rd inversion | Bb D# C E G | C7#9/Bb | |
| 4th inversion | D# C E G Bb | C7/Eb (also read as C7#9/D#) |
Where C7#9 fits
C7#9 has no place among the chords built from a major or minor scale: it holds a major third, E, and the sharp ninth D#, which sounds the same as the minor third. That major–minor clash is the blues in one chord. It is used as the I chord of a blues or a funk vamp, and as a tense V chord in jazz; Jimi Hendrix's "Purple Haze" made E7#9 famous, which is why guitarists call it the Hendrix chord.