C7-9 (C7b9) altered chord
Altered C chord for piano presented by keyboard diagrams.
Explanation: The C7-9 alter the C9 by the change of one note. The chord name can also be written as C7b9 or C7(b9).
Theory: The C7-9 are identical with the C9 except that the major ninth is flattenedThe tone is one half step lower.
Notes: C - E - G - Bb - Db