Definition
Two chords are in a chromatic mediant relationship when their roots are a major or minor third apart, they have the same quality (both major or both minor), and they share only one common tone. They are "chromatic" because at least one note is altered with respect to the starting scale.
Conservative definition (Forte and others): in C major the chromatic mediants of C are E, Ab, A, Eb. Broader definition (Benward–Saker): chords of opposite quality with no common tones are added, Ebm and Abm (the "doubly chromatic" ones).
Table in C major
| Chord | Relationship | Common tone | Motion of the other voices |
|---|---|---|---|
| E (E G# B) | upper mediant (III) | E | C → B, G → G# |
| Eb (Eb G Bb) | upper mediant (bIII) | G | C → Bb, E → Eb |
| A (A C# E) | submediant (VI) | E | C → C#, G → A |
| Ab (Ab C Eb) | submediant (bVI) | C | E → Eb, G → Ab |
| Ebm (Eb Gb Bb) | doubly chromatic | none | C → Bb, E → Eb, G → Gb |
| Abm (Ab Cb Eb) | doubly chromatic (hexatonic pole) | none | C → Cb, E → Eb, G → Ab |
In all cases the voices move by half step or whole step: very economical voice leading, but the harmonic result is distant. This contrast (close voices, distant keys) is the secret of the "magical" effect.
Why they sound this way
- There is no dominant relationship: the mind does not hear "tension and resolution" but a change of light, like a film cut.
- The common tone holds the thread; the altered note (G#, Bb, C#, Eb) gives the color.
- Upward in major (C → E) it sounds bright and epic; downward with flats (C → Ab, C → Eb) it sounds darker and more Romantic.
Historical uses
- Schubert and Beethoven: modulations by third. In Beethoven's Waldstein Sonata, Op. 53, the second theme of the exposition is in E major instead of the dominant G: a chromatic mediant of C.
- Liszt, Wagner, Bruckner: chains of thirds that weaken the tonality.
- In jazz: Linus and Lucy by Vince Guaraldi highlights the bIII; the Coltrane changes are a cycle of major-third mediants.
Uses in pop, rock, and film
- I – bVI – bVII – I (C Ab Bb C): the "heroic ending" of video games (the so-called Mario cadence) and of stadium rock.
- I – III (G → B) in Creep by Radiohead: B major is a chromatic mediant of G.
- In film music, chromatic mediants are the language of "wonder": Frank Lehman (Hollywood Harmony, 2018) documents them extensively in Hollywood scores.
The hexatonic pole
C ↔ Abm is the most extreme relationship: all three voices move by a half step, with no common tone. Richard Cohn called it the hexatonic pole and showed how in the nineteenth century it is associated with "uncanny" meanings (death, the supernatural). In horror or fantasy film it works very well.
How to write them well
- Keep the common tone in the same voice (same register): it is the glue.
- Move the other voices by step: no leaps.
- Prepare the mediant with a clear tonal chord, so that the change is perceived.
- You can "justify" it functionally afterward: E → Am (E as V/vi), Ab → G (bVI → V), Eb → Dm7 G7 (return with ii–V).
Exercise for the producer
- Pad on C (C E G) for 2 bars.
- Move to Ab (C Eb Ab): hold C, move E → Eb and G → Ab.
- Then to E (B E G#) and back to C. The cycle C – Ab – E – C: you have traveled through the three keys of an augmented triangle (C, Ab, E), a small version of the Coltrane changes.
- Add a string line in octaves on the common tone to emphasize the thread.
Related topics
Neo-Riemannian theory (P, L, R), Tonnetz, Coltrane changes, harmony for film music, chromatic and direct modulation.