Major thirteenth

The major thirteenth (M13) spans 21 semitones. It is the compound form of a major sixth and serves as a lush upper extension in modern harmonic language.

Construction and spelling

M13 is built as an octave plus major sixth, for example C-A above the octave. It can be heard as a high color tone in extended chord voicings. Spelling preserves thirteenth-function context.

Harmonic and melodic usage

Harmonically, M13 appears in major/minor 13th sonorities and rich jazz-pop voicings. Melodically, it creates very wide, expressive contour. It often contributes warmth rather than harsh tension.

Examples

• 13th chord voicings with selective upper tones
• Color extensions over tonic and dominant functions
• Large melodic intervals in cinematic writing

In practice

Practice M13 with M6 comparison to hear the same quality across registers. Explore voicings that balance 9, 11, and 13 color tones. This improves extension control and arranging fluency.