C7(b13) chord on ukulele
C7(b13) is the dominant flat thirteenth chord: C, E, G, Bb and Ab (1–3–5–b7–b13). On ukulele, the diagram shape is 1 0 0 1, with C in the bass.
On the ukulele, the high reentrant G makes every shape light — and with four strings, every note is exposed. In this C7(b13) voicing the bass is C and the shape sits at fret 1, ringing 2 open strings. Because this instrument has fewer strings than C7(b13) has notes, one note, usually the fifth, is normally dropped without losing the chord's identity. Its soft nylon strings sound warm and mellow, light enough to float gently over a song.
Notes and formula of C7(b13)
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.
Where to use it
A dark resolution, especially to a minor chord.
See also
Part of the Altered dominants family.