Sub-mediant

In music, the submediant is the sixth scale degree of the diatonic scale, the ' mediant', halfway between the tonic and the subdominant or 'lower dominant'. It is also the third factor of the subdominant (IV) triad. It is occasionally called superdominant, as the degree above the dominant (see also below, "Theory"). It is sung la in solfege. In music theory, the submediant chord is symbolized by the Roman numeral VI if it is major or vi if it is minor.

In the C major scale (white keys on a piano, starting on C), the submediant is the note A; and the submediant chord is A-minor, consisting of the notes A, C, and E. Therefore, Am is the vi chord in the C major scale. The scales of C major and A (natural) minor have the property of sharing the same notes: they are said to be the relative of each other, and the C major and A minor chords are also said the relative of each other. In the A natural minor scale (same white keys, now starting on A), the submediant is the note F; and the submediant chord is F-major, consisting of the notes F, A, and C. Therefore, F is the VI chord in the A (natural) minor scale. These chords (and the corresponding keys) cannot be said to be relative of each other, however, because their scale is not the same: the F major scale includes a B♭ which is absent in the A minor scale.

Since the submediant chord is minor in a major key, and major in a minor key, it provides contrast with its tonic chord. Similarly, submediant and tonic keys contrast with each other even although they may make use of the same scale.

One of the main usages of the submediant chord is in the deceptive cadence, V⁷–vi in major or V⁷–VI in minor.

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