Minor ninth

The minor ninth (m9) spans 13 semitones. It is the compound form of the minor second and is one of the sharpest extension tensions in tonal and jazz harmony.

Construction and spelling

m9 is built as an octave plus minor second, for example C-Db above the octave. It keeps clear semitone friction while expanding register. The spelling preserves ninth-function context.

Harmonic and melodic usage

Harmonically, m9 appears in altered dominants, minor-major tensions, and dramatic color chords. Melodically, it creates urgent pull and expressive instability. It is used when strong directional tension is desired.

Examples

• b9 color on dominant-function chords
• Dense film-score textures with high tension
• Expressive melodic leaps emphasizing conflict

In practice

Practice m9 against m2 to hear identical quality in compound range. Resolve m9 to stable tones to internalize tension-release behavior. This improves control of dissonant extensions.