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Chord & Fret

C#7(b9) — dominant flat ninth

Also written Db7(b9) — the same chord, spelled the other way.

Notes in C#7(b9): C# – E# – G# – B – DFormula: 1 – 3 – 5 – b7 – b9

In the formula, the numbers count steps of the major scale starting from the note that names the chord; "b" lowers a half step, "#" raises one — and a slash names the bass note.

The 7(b9) is a dramatic dominant. The minor ninth intensifies the resolution, especially when the target chord is minor.

The same chord on all four instruments

C#7(b9), x 4 0 1 0 1C#7(b9)312×DbDAbBF
Guitar
C#7(b9), x 4 0 1 0 1C#7(b9)312×DbDAbBF
Electric guitar
C#7(b9), 3 6 0 0C#7(b9)312FDbBD
Cavaquinho
C#7(b9), 4 2 1 4C#7(b9)3214BDFDb
Ukulele

Where to use it: A dominant that resolves to a minor chord.

This is just one shape of C#7(b9). In Chord & Fret, you check it note by note, playing any shape as an arpeggio; compare positions with their difficulty marked; and set a capo — the diagrams redraw above it. Start free. Unlock everything with Pro. Plays offline.

See the whole neck in Chord & Fret →

Part of the Altered dominants family.

Other chords in this family

Db7(#9)Db7(#11)C#7(b13)Db7alt

See all chord types and qualities →