The diminished major seventh chord stacks a diminished triad with a major seventh above the root (1-♭3-♭5-7). It is famous for its uncanny stability–instability mix: the diminished triad wants to move, but the major seventh adds a strange luminous ceiling. It appears in classical and film harmony as a color chord and in jazz as an occasional reharmonization device.
Construction
Formula: 1-♭3-♭5-7. In CoM7, spell C-E♭-G♭-B (enharmonic spellings vary).
Usage
Suspense cues, pivot chords, and brief chromatic clouds over a clear bass.
Examples
- Film scoring for psychological tension
- Late Romantic harmony with diminished colors
- Modern jazz voicings as passing color
Play
Voice the major seventh clearly; avoid doubling that creates unclear tendency tones.
Ear-training cues
Diminished triad interior with a major seventh above the root—eerie, bright-dark.
