Major seventh
Eleven semitones, a semitone below the octave — rich in tension and floating.
What it means
The major seventh comprises eleven semitones and thus lies a semitone below the octave. In the major scale it arises between the root and the seventh degree, that is, between the tonic and the leading tone. It counts as dissonant, and its tension stems precisely from the nearness to the octave: the ear expects the resolution upward.
Musical use
In the classical study of composition the major seventh appears above all as a suspension or as a passing formation; as a free chord tone it was long not usual. The dominant seventh chord contains the minor seventh, not the major — the difference is decisive, for the minor seventh falls downward, whereas the major strives upward to the octave.
In jazz and popular music, by contrast, the major seventh is a self-evident chord component: the major triad with a major seventh sounds soft and floating, without the urgent direction of the dominant seventh chord. Because the term here comes from jazz, designation with chord symbols is usual in this milieu.
In inversion the major seventh becomes the minor second — both are the same relationship of tension in different registers. As a wide interval the seventh sounds distinctly more open and less sharp than the closely lying second.
In jazz the major seventh is a fixed component of the major seventh chord, which is used as a tonic sonority and sounds soft and floating. In classical harmony it appears as a suspension, passing note, or as the seventh of the seventh chord on the first and fourth degrees and is resolved stepwise downward. Melodically it is seldom leapt, because it is hard to sing; where it happens, the leap seems conspicuous and expressive.
Performance practice
Do not sing the major seventh as a leap into the uncertain but as octave minus semitone or as the leading tone above the root — both hit more securely. Watch the direction of resolution: upward to the octave. And intonate it rather high when it has leading-tone character; as a resting chord tone, by contrast, it tolerates a more relaxed position.