C13 chord on cavaquinho
C13 is the dominant thirteenth chord: C, E, G, Bb, D and A (1–3–5–b7–9–13). On cavaquinho, the diagram shape is 7 5 5 8, with A in the bass.
On the cavaquinho, four steel strings tuned D–G–B–D pack the chord into a small, bright space — every finger counts. In this C13 voicing the bass is A and the shape runs from fret 5 to 8. Because this instrument has fewer strings than C13 has notes, one note, usually the fifth, is normally dropped without losing the chord's identity. Its four steel strings give a bright, sharp attack that cuts through the mix and drives the beat.
Notes and formula of C13
Notes in C13: C – E – G – Bb – D – AFormula: 1 – 3 – 5 – b7 – 9 – 13In 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
An elegant dominant in jazz, MPB and gospel.
See also
Part of the Extended family.