A major seventh chord is a chord composed of four notes, where the distance between the first and the second note is four semitones, the distance between the second note and the third note is three semitones, and the distance between the third note and the fourth note is four semitones.
The C major seventh chord, for example, is Cmaj7 and consists of the notes C, E, G, and B. There are four semitones between C and E. There are three semitones between E and G. There are four semitones between G and B.
The major seventh chord can also be described as composed of the major third, the perfect fifth, and the major seventh of some scale. In the major scale in C, for example, the third note is E. E is a major third, because the interval between the first note C and E is four semitones. The fifth note on the scale is G. It is a perfect fifth, as the interval between the first note C and G is seven semitones. The seventh note is B. It is a major seventh, as the interval between the first note C and B is eleven semitones.
The major seventh chord is a major chord with the added major seventh.
Examples of scales with major seventh chords
The following are examples of where the major seventh chord occurs in common heptatonic scales.
- On the first note (the tonic) and fourth note (subdominant) of the major scale (the Ionian scale). That is, if a major seventh chord is composed over the first or fourth note on the major scale, then all notes in that chord will also be on the major scale.
- On the third (median) and sixth (submediant) note of the minor scale (the Aeolian scale).
- On the sixth note (the submediant) of the harmonic minor scale.
- On the second note (the supertonic) of the Spanish gypsy scale.
Examples of relationships between the major seventh chord and other four note chords
Shifting the fourth note of the major seventh chord one semitone down produces a dominant seventh chord (i.e., switching from a major seventh to a minor seventh).
Shifting the second note of the major seventh chord one semitone down produces a minor-major seventh chord (i.e., switching from a major third to a minor third).
Shifting the second note of the major seventh chord one semitone down and the fourth note one semitone down produces a minor seventh chord (i.e., switching from a major third to a minor third and from a major seventh to a minor seventh).