Chromatic mediant, mediant, and submediant are all terms used in music theory to describe different types of chords and harmonic relationships. While they share some similarities, they also have some key differences.

The mediant and submediant

The mediant and submediant are both scale degrees that are located a third away from the tonic. The mediant is the third degree of the scale, while the submediant is the sixth degree of the scale. Both the mediant and submediant can be used to build chords and are often used in chord progressions to create harmonic interest and variety. However, the chords built on the mediant and submediant are typically diatonic chords, meaning they are built using only the notes of the key in which they are being used. For example, in the key of C major, the mediant chord is E minor, and the submediant chord is A minor.

Chromatic mediants

Chromatic mediants, on the other hand, are chords that are built on the mediant degree of a parallel key, but with one or more notes chromatically altered. For example, in the key of C major, the mediant chord is E minor. The chromatic mediants of C major would be chords built on the mediant degree of the parallel minor key of C minor or the mediant degree of the parallel major key of C-sharp major. The chords would be E-flat major and G-flat major, respectively. These chromatic mediants add a unique harmonic color and can provide an unexpected twist in a chord progression.

In summary, the mediant and submediant are diatonic chords that are built on the third and sixth degrees of the scale, respectively. Chromatic mediants, on the other hand, are non-diatonic chords that are built on the mediant degree of a parallel key, with one or more notes chromatically altered.

Usage

In general, the mediant and submediant chords are more commonly used than chromatic mediants, as they are diatonic to the key and therefore blend more naturally with the other chords in the progression. However, chromatic mediants can add a unique and unexpected twist to a chord progression and are often used for that reason.

Chromatic mediants specifically are commonly used in film music, particularly in dramatic and suspenseful scenes. Because chromatic mediants create a sense of tension and surprise, they can be effective at heightening the emotional impact of a scene in a film or television show.

For example, a common chord progression used in film music is I-vi-III-IV, which features a chromatic mediant chord (III) between the submediant (vi) and subdominant (IV) chords. This progression is often used in emotional or suspenseful scenes to create a sense of tension and anticipation.

Another common use of chromatic mediants in film music is to introduce a new musical theme or motif. For example, a composer may use a chromatic mediant chord to introduce a new theme or character, helping to create a unique and memorable musical identity.

Overall, mediants and submediants are versatile and powerful tools in a composer’s arsenal, capable of evoking a range of emotions and moods in various musical genres. From creating a sense of resolution and tension to modulating to new keys, these chords add harmonic interest and complexity to music and are essential components of many memorable melodies and chord progressions.