Major seventh

A semitone below the octave

The major seventh lies only a semitone below the octave and “pulls” upwards with great tension. With the ratio 15:8 it sounds strongly dissonant, almost painful, and asks for resolution into the octave. It is one of the most complex ratios in the natural harmonic series and counts as a “derived” interval: it arises only by stacking lower partials, in just intonation from a major third plus a perfect fifth (5/4 times 3/2).

From dissonance to colour

In traditional harmony the major seventh counted as a sharp dissonance, mostly treated as a passing note or suspension and resolved. In jazz it became a characteristic pleasing sound: the maj7 chord, say Cmaj7 with C–E–G–B, became the trademark of bossa nova, smooth jazz and romantic ballads. There the tension is no longer resolved but enjoyed as a colour: a mild, soft, shimmering sound. As a melodic leap the major seventh is rare; when it occurs, it sounds yearning or dramatic.

On the guitar

Eleven frets above the open string: on the high E string (329.63 Hz) D♯ sounds at the 11th fret. The 11th fret lies very close to the 12th, the octave, and this very closeness creates the strong tension. In maj7 chord voicings on the guitar the major seventh often lies as the top note, which gives the chord its shimmering gleam. As a harmonic it is hardly practicable: the 15th partial lies too close to the bridge.

Common mistakes

• Confusing it with the minor seventh: Eleven against ten semitones.
• Treating the major seventh as a mistake: In jazz it is a deliberate sound.
• Equating it with the leading tone: The leading tone is a degree, the major seventh an interval above the root.