C7(b13) chord: dominant flat thirteenth
C7(b13) is the dominant flat thirteenth chord on C: C, E, G, Bb and Ab (1–3–5–b7–b13). C7(b13) stacks the root C, the major third E, the perfect fifth G, the minor seventh Bb and the minor thirteenth Ab. The 7(b13) is a dark dominant, with the thirteenth lowered.
Notes in C7(b13): C – E – G – Bb – AbFormula: 1 – 3 – 5 – b7 – b13In 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 tension pulls strongly toward resolution.
The same chord on all four instruments
Where to use it
A dark resolution, especially to a minor chord.
Part of the Altered dominants family.