The 7♯9♭13 dominant combines gritty upper tension with dark lowered-thirteenth color. It keeps dominant force but sounds heavier and more dramatic than 7♯9 alone. This is a high-expression chord often used right before a strong harmonic landing.
Construction
Practical formula: 1-3-5-♭7-♯9-♭13. In C: C-E-G-B♭-D♯-A♭. 3 and ♭7 provide function; ♯9 and ♭13 create altered identity.
Usage
Useful in modern jazz, blues-jazz hybrids, and cinematic suspense harmony. It works especially well before minor or modal destinations.
Play
Keep guide tones stable and spread ♯9/♭13 so the contrast remains clear. Resolve at least one altered tone by semitone for direction.
