Dominant 9th #5
9#5
0 - 4 - 8 - 10 - 14Dom7#5 + major 9th
About Dominant 9th #5
A dominant ninth sharp five chord is a dominant ninth with a raised fifth — in C that is C, E, G♯, B♭ and D, written C9♯5. Like its flat-five relative it lives entirely inside the whole-tone scale, and the two chords are the pair that scale produces on any root.
Notes and formula
The formula is 1 – 3 – ♯5 – ♭7 – 9, or 0 – 4 – 8 – 10 – 14 in semitones. The fifth is raised, the ninth is natural.
C, D, E, G♯ and B♭ are all drawn from one whole-tone scale, which the chord shares with C9♭5 — the two differ by which of the scale's notes is called the fifth.
How it sounds
Bright and untethered. The raised fifth pushes upward, the natural ninth keeps the chord warm, and the missing perfect fifth means nothing holds it to a root.
Compared with the flat-five version it sounds more optimistic — the alteration moves away from the root rather than toward it, and the ear follows.
How to play it
On guitar the movable form is x–3–2–3–3–4, sounding C–E–B♭–D–G♯. Every note carries information here, which is unusual for a five-note dominant.
On piano the useful voicing is C in the left hand and E–B♭–D–G♯ in the right, with the raised fifth on top where it can be heard as a colour rather than as a wrong note.
Where it appears
In big-band writing as a dominant with more lift than a plain ninth. In impressionist piano, where whole-tone colour is the point. In musical-theatre arranging, where the chord is a stock device before a key change.
It is also what a plain dominant ninth becomes when an inner voice rises from the fifth to the sixth — the chord is often the by-product of a line rather than a decision.
Sharp five or flat thirteen
C9♯5 and C9♭13 name the same pitch with different implications. C9♯5 says the fifth has moved; C9♭13 says a note has been added above a fifth that may still be sounding.
In a five-note chord the distinction is real: with the perfect fifth present the chord is anchored, without it the chord belongs to the whole-tone world.
Scales that contain it
The whole-tone scale, exactly. It is the same scale that fits C9♭5, which is why the two chords substitute for each other freely.
The altered scale fits partly — it contains the raised fifth but not the natural ninth, so it changes the chord's character rather than matching it.
Frequently asked questions
What notes are in a C9♯5 chord?
C, E, G♯, B♭ and D. On guitar, x–3–2–3–3–4.
How is it different from 9♭5?
Which note of the same whole-tone scale is called the fifth. Both chords come from that scale, and they substitute for each other easily.
Is ♯5 the same as ♭13?
The same pitch. Sharp five means the fifth has been replaced; flat thirteen means a note has been added above a fifth that may still be present.