C7#9 guitar chord
The standard grips this chord is usually shown with.
- Tap a note to hear it
- Arrows change position
- Fingers, notes or intervals
- Play the chord
About C7#9 — 1st inversion
C7#9 is C, E, G, Bb and D# — C9 with the ninth raised a semitone.
It sounds gritty and contradictory. The minor third sounding over the major third; every guitarist knows it as the Hendrix chord.
Altered dominant — dominant function with a blues third on top.
C7#9 notes and formula
| C | E | G | Bb | D# |
|---|---|---|---|---|
| 1 | 3 | 5 | ♭7 | ♯9 |
Also written C7(#9), C7+9 or C7♯9. The same chord either way; which spelling you meet depends on who wrote the chart.
How to play C7#9
C7#9 in 1st inversion puts E in the bass instead of C, the 3rd of the chord. The notes are the same; what changes is what the bass line does, which is most of why you would reach for it — it lets the lowest voice move by step where the root would have jumped.
One of C7#9’s 9 common shapes does this:x78888
Play C7#9 as a shell — root, third and seventh — and the spare string takes the #11 (F#), the b13 (Ab) or the 13 (A).
All 9 common shapes as fret numbers, lowest string first. Hover or tap one to see it drawn.
- x3234x, 2nd fret, C, root position, top note D#, all fretted
- x35340, open position, C, root position, top note E, 1 open string
- x65556, 5th fret, D#, 9th in the bass, top note Bb, barred
- 8788xx, 7th fret, C, root position, top note D#, barred
- x78888, 7th fret, E, 1st inversion, top note C, barred
- 8-10-8-9-8-11, 8th fret, C, root position, top note D#, barred
- 8-10-8-9-11-11, 8th fret, C, root position, top note D#, all fretted
- x-x-10-9-11-11, 9th fret, C, root position, top note D#, all fretted
- x-10-10-9-11-11, 9th fret, G, 2nd inversion, top note D#, all fretted
How to use C7#9
C7#9 is a dominant with its tension raised, so it still points at F — harder than a plain seventh does, because the altered tones sit a semitone from where they are going.
In a phrase:Gm7→C7#9→Fmaj7— the ii–V–I of F.
Voice by voice, C7#9 → F. 2 voices move by a semitone, and one note is common to both chords.
| In C7#9 | Moves | In F |
|---|---|---|
| C, the root | stays where it is | C, the fifth |
| E, the major third | rises a semitone | F, the root |
| G, the fifth | falls a whole tone | F, the root |
| Bb, the flat seventh | falls a semitone | A, the major third |
| D#, the sharp ninth | rises a whole tone | F, the root |
What to play over C7#9
Every note of C7#9 is in C half-whole diminished.
Chords near C7#9
Change one note of C7#9 and you have Cm7 (drop the major third), Cm9 (the major third becomes the ninth), C7 (drop the sharp ninth), C7/G (drop the sharp ninth), C9 (the sharp ninth becomes the ninth) or C7b9 (the sharp ninth becomes the flat ninth).
C7#9 is an altered chord — a dominant seventh with its fifth or ninth moved. Altered dominant chords on every root.
The common shapes and the derived voicings come from different places, and both are explained in how this site is built.