B flat Major add flat ninth

The major add ♭9 chord is a major triad with a lowered ninth added and no seventh in the symbol. That makes it different from maj7♭9: you keep the simpler tertian stack of a major triad, but you import a dramatic semitone clash right above the root. It is primarily a color and suspense chord—common in film scoring, modern jazz harmony, and contemporary production when you want “major-side” stability with an immediate sting of chromatic tension.

Construction

Core formula: 1-3-5-♭9. In C(add♭9), a spelling might be C-E-G-D♭. Because root and ♭9 are a minor second apart, register and doubling matter: wide spacing or octave displacement often sounds better than stacking them in the same tight octave.

Usage

Use sparingly as a spotlight sonority, a passing chord, or a reharmonization surprise on tonic-related harmony. It can also prepare a resolution by moving the ♭9 down by step into chord tones of the next harmony.

Examples

• Film and game cues that need instant harmonic unease on a major frame
• Modern jazz reharmonizations as a brief pivot
• Experimental pop production for a single bar of harmonic spice

Play

Keep the major third clear so the ear still recognizes major quality, separate root and ♭9 when possible, and resolve the ♭9 with intention so the dissonance feels composed rather than accidental.

Ear-training cues

Listen for a minor second between root and ♭9 sitting on top of a major triad—without the pull of a seventh chord.