A minor seventh chord is a chord composed of four notes, where the distance between the first and the second note is three semitones, the distance between the second note and the third note is four semitones, and the distance between the third note and the fourth note is three semitones.
The E minor seventh chord, for example, is Em7 and consists of the notes E, G, B, and D. There are three semitones between E and G. There are four semitones between G and B. There are three semitones between B and D.
The minor seventh chord can also be described as composed of the minor third, the perfect fifth, and the minor seventh of some scale. In the minor scale in E, for example, the third note is G. G is a minor third, because the interval between the first note E and G is three semitones. The fifth note on the scale is B. It is a perfect fifth, as the interval between the first note E and B is seven semitones. The seventh note is D. It is a minor seventh, as the interval between the first note E and D is ten semitones.
The minor seventh chord is a minor chord with the added minor seventh.
Examples of scales with minor seventh chords
The following are examples of where the minor seventh chord occurs in common heptatonic scales.
- On the first note (the tonic), fourth note (subdominant), and fifth note (dominant) of the minor scale (the Aeolian scale). That is, if a minor seventh chord is composed over the first, fourth, or fifth note on the minor scale, then all notes in that chord will also be on the minor scale.
- On the third (median), sixth (submediant), and seventh note (subtonic) of the major scale (the Ionian scale).
- On the fourth note (the subdominant) of the harmonic minor scale.
- On the second note (the supertonic) of the melodic ascending minor scale.
- On the third note (the median) of the altered scale.
- On the seventh note (the subtonic) of the Spanish gypsy scale.
Examples of relationships between the minor seventh chord and other four note chords
Shifting the second note of the minor seventh chord one semitone up and the fourth note one semitone up produces a major seventh chord (i.e., switching from a minor third to a major third and from a minor seventh to a major seventh).
Shifting the third note of the minor seventh chord one semitone down and the fourth note one semitone down produces a diminished seventh chord (i.e., switching from a perfect fifth to a diminished fifth and from a minor seventh to a diminished seventh).