Minor seventh

What it means

The minor seventh comprises ten semitones, that is, a whole tone below the octave. It counts as dissonant and as a rule resolves downward. It plays its most important role in the dominant seventh chord: if one adds a minor seventh to the major triad on the fifth degree, the sonority arises that carries the cadence.

Musical use

In the V7, the minor seventh forms the tritone together with the third, and the close lives from its resolution: the seventh falls to the third of the tonic, the leading tone rises to the root. This interval is thus the actual engine of functional harmony — only it turns an arbitrary major triad into a sonority that points unambiguously toward a goal.

In the study of composition the seventh is prepared and resolved downward; in the course of time these rules loosened until the dominant seventh chord could be used freely. The half-diminished and the diminished seventh chord also contain sevenths, the former a minor one over a diminished triad, the latter a diminished one.

Melodically the minor seventh arises between the root and the seventh degree in the Mixolydian key as well as in natural minor. In inversion it becomes the major second.

It is to be distinguished from the major seventh, which is a semitone wider and strives upward: the difference decides whether a chord pushes or floats.

The minor seventh is in classical harmony a dissonance that is resolved downward. In blues, jazz, and rock music, by contrast, it is felt as a stable part of chords. It is the interval between the seventh partial of the harmonic series and the root, which, however, in the natural series lies lower than the tempered seventh.

Performance practice

Lead the seventh downward and give it weight beforehand — the resolution works only if the tension was audible. Do not intonate it too high; it wants to fall. For singing it helps to derive it from the familiar dominant seventh chord instead of hitting it in isolation.