Dominant 7th #5 b9
7#5b9
0 - 4 - 8 - 10 - 13Dom7 with augmented 5th and minor 9th
About Dominant 7th #5 b9
A dominant seventh sharp five flat nine chord raises one degree and lowers another — in C that is C, E, G♯, B♭ and D♭, written C7♯5♭9. It is the dominant of the harmonic minor scale with one further alteration, and it sounds like it: dramatic, tightly wound, and unmistakably heading somewhere minor.
Notes and formula
The formula is 1 – 3 – ♯5 – ♭7 – ♭9, or 0 – 4 – 8 – 10 – 13 in semitones. The fifth goes up, the ninth comes down.
The two alterations move in opposite directions, which spreads the chord rather than clustering it — D♭ near the bottom of the upper structure, G♯ above the third, and nothing sitting adjacent to anything else.
Where it comes from
The fifth mode of harmonic minor supplies a dominant with a flattened ninth and a lowered thirteenth. Raise that thirteenth to a sharp fifth and this chord appears — which is why it belongs so firmly to minor keys.
In C minor the chord on G with these alterations is the most emphatic cadence available without leaving the key's own scale material behind entirely.
How to play it
On guitar the movable form is x–3–2–3–2–x with the fifth raised on an inner string; in practice players use x–3–x–3–2–4, sounding C–B♭–D♭–G♯ and leaving the third to the bass or another instrument.
On piano the clear voicing is C low, then E–B♭–D♭ with G♯ at the top. Keeping the two alterations apart is what makes the chord legible.
How it sounds
Operatic. The flattened ninth carries the diminished colour of a classical cadence and the raised fifth adds a second voice pushing upward, so the chord reads as high drama rather than as blues grit.
That is the practical distinction from its sharp-nine cousin: same degree of tension, entirely different genre.
Where you hear it
In minor-key jazz standards, at the cadence. In tango and in gypsy jazz, where harmonic minor is the ordinary scale rather than a colour. In film scoring, wherever a minor resolution needs weight.
It also appears in metal and progressive rock, which inherited harmonic-minor harmony from the classical repertoire rather than from jazz.
Scales that contain it
The altered scale fits, and so does the fifth mode of harmonic minor if the raised fifth is treated as a passing alteration. The two give noticeably different flavours over the same chord.
The half–whole diminished scale contains the flattened ninth but not the raised fifth, so it fits only if the voicing omits that note.
Frequently asked questions
What notes are in a C7♯5♭9 chord?
C, E, G♯, B♭ and D♭. On guitar, x–3–x–3–2–4.
Why does it sound classical rather than bluesy?
The flattened ninth. It carries the diminished sound of a harmonic-minor cadence, where the raised ninth of the other altered dominants carries the blues clash between two thirds.
Which key does it belong to?
Minor, almost always. The chord is the dominant of a harmonic minor scale with the thirteenth raised, and it resolves to a minor tonic.