C sharp Dominant seventh flat thirteenth

The 7♭13 dominant keeps the core dominant sound while adding a darker upper extension. Compared with plain 7, it feels more dramatic and often more directional toward minor or modal destinations.

Construction

Practical formula: 1-3-5-♭7-♭13. In C: C-E-G-B♭-A♭. The 3 and ♭7 define function; ♭13 supplies darker color.

Usage

Common in jazz, blues-influenced harmony, and minor-key cadences. It works well when you want tension without using many simultaneous alterations.

Play

Keep guide tones stable, voice ♭13 clearly above the chord, and resolve by semitone when possible.