C#7#9 guitar chord
Root, third and seventh: the guide tones fix the quality, so the fifth is dropped. That is what leaves a string free, so pick a tension to put on top.
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About C#7#9 — shell voicings
C#7#9 is C#, E#, G#, B and E — C#9 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.
C#7#9 notes and formula
| C# | E# | G# | B | E |
|---|---|---|---|---|
| 1 | 3 | 5 | ♭7 | ♯9 |
Altered dominant — dominant function with a blues third on top.
Also written C#7(#9), C#7+9 or C#7♯9. The same chord either way; which spelling you meet depends on who wrote the chart.
How to play C#7#9
Root, third and seventh. The third and seventh, the guide tones, are what make the chord major, minor or dominant, so the fifth can go: it says nothing the symbol needs.
Three notes means a spare string, which is the real point. Put a tension on it.
C#7#9 has 3 of them, on the middle four strings, the bottom four strings and the top four strings, from the 3rd fret up to the 10th — all in one inversion, so the bass note never moves. The one to learn first is the C# shape at the 3rd fret, which is the easiest grip here.
Start with x43420 — no barre and 1 open string. 1 of the 9 shapes here sits in open position. 4 of the 9 need a barre. Together they cover the neck from the 2nd fret to the 12th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x43420 | open position | C#, root position | E | 1 open string |
| x4345x | 3rd fret | C#, root position | E | all fretted |
| x76667 | 6th fret | D##, 9th in the bass | B | barred |
| 9899xx | 8th fret | C#, root position | E | barred |
| x89999 | 8th fret | E#, 1st inversion | C# | barred |
| 9-11-9-10-9-12 | 9th fret | C#, root position | E | barred |
| 9-11-9-10-12-12 | 9th fret | C#, root position | E | all fretted |
| x-x-11-10-12-12 | 10th fret | C#, root position | E | all fretted |
| x-11-11-10-12-12 | 10th fret | G#, 2nd inversion | E | all fretted |
The same notes rebuilt from scratch give 12 drop 2, 8 drop 3, 13 rootless and 6 open string voicings, each on its own page.
Tensions. A shell of C#7#9, root, third and seventh, leaves a string free, and the tones that belong over it are the #11 (F##), the b13 (A) and the 13 (A#).
How to use C#7#9
C#7#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.
Voice by voice, C#7#9 → F#. 2 voices move by a semitone, and one note is common to both chords.
| In C#7#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 |
| B, the flat seventh | falls a semitone | A#, the major third |
| E, the sharp ninth | rises a whole tone | F#, the root |
What to play over C#7#9
Every note of C#7#9 is in C# half-whole diminished.
Chords near C#7#9
Change one note of C#7#9 and you have C#m7 (drop the major third), C#m9 (the major third becomes a ninth), C#7 (drop the minor third), C#9 (the minor third becomes a ninth) or C#7b9 (the minor third becomes a flat ninth).
C#7#9 is an altered chord — a dominant seventh with its fifth or ninth moved. Altered dominant chords on every root.
On C#7#9’s sound and use this page follows Mark Levine, The Jazz Theory Book (Sher Music, 1995). The shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.