Dominant 13th #9
13#9
0 - 4 - 7 - 10 - 15 - 21Dom13 with augmented 9th
About Dominant 13th #9
A dominant thirteenth sharp nine chord pairs the blues clash of a raised ninth with the warmth of a natural thirteenth — in C that is C, E, G, B♭, D♯ and A, written C13♯9. It is the chord that lets a horn section sound gritty and full at the same time, and it is everywhere in soul and funk arranging.
Notes and formula
The formula is 1 – 3 – 5 – ♭7 – ♯9 – 13, or 0 – 4 – 7 – 10 – 15 – 21 in semitones. The raised ninth sits an octave and a minor third above the root; the thirteenth is natural.
As with the flat-nine version, the pairing points to a scale. The altered scale has no natural thirteenth, so a chord holding both a raised ninth and a natural thirteenth comes from the half–whole diminished scale instead.
How it sounds
Gritty and generous at once. The raised ninth supplies the clash between a major and a minor third that the blues has always used, and the thirteenth gives the chord enough consonance to be held rather than jabbed.
That combination is why the chord survives being played by three horns at full volume, where a plain sharp-nine dominant would sound harsh.
How to play it
On guitar the movable form is x–3–2–3–4–5, sounding C–E–B♭–D♯–A. The stretch is real, and players often drop the root and let the bass carry it.
On piano the standard voicing is C low, then E–B♭–D♯–A. Keeping the raised ninth above the seventh is what makes it read as an alteration rather than as a wrong third.
Where you hear it
Soul and funk horn writing, where the chord is a stab rather than a pad. Big-band shout choruses. Blues-based jazz, on the V chord of a twelve-bar.
It is also common in gospel, where a dominant that is both rough and warm suits a full band better than the sharper altered chords do.
Against its neighbours
C7♯9 is the same alteration without the thirteenth — the Hendrix chord, harsher and more exposed. C13♭9 lowers the ninth and turns the colour from blues to drama.
All three come from the same family of dominants and none of them substitutes cleanly for the others: the choice sets the genre of the bar.
Scales that contain it
The half–whole diminished scale contains every note. The altered scale contains the raised ninth but not the natural thirteenth, so it fits only if the arrangement drops that note.
Over a blues, players often use the minor pentatonic instead and let the chord supply the sophistication. The raised ninth means nothing in that scale will clash.
Frequently asked questions
What notes are in a C13♯9 chord?
C, E, G, B♭, D♯ and A. On guitar, x–3–2–3–4–5.
How is it different from 7♯9?
The thirteenth. The plain sharp-nine chord is harsher and more exposed; adding the thirteenth gives it enough consonance to be held under an arrangement.
Which scale fits?
The half–whole diminished scale, because it contains both the raised ninth and the natural thirteenth. The altered scale lacks the thirteenth.