THE MEDIANT & SUBMEDIANT
This is a supplement to The Complete Musician Chapter 13: The Submediant (A New Diatonic Harmony, and Further Extensions of the Phrase Model), and Chapter 14: The Mediant, the Back-Relating Dominant, and a Synthesis of Diatonic Harmonic Relationships
WHAT IS THE MEDIANT?
MEDIANT is a fancy word for the note and the chord built off the third scale degree (3 - 5 - 7). To help you remember, consider how “mediant” starts with the syllable “mi” (as in the third scale degree in solfege). In a major scale, this chord is minor (iii), in a minor scale, this chord is major (III). Because it carries the opposite quality of the home key and two of its pitches are found in the tonic chord (3 and 5) with the final pitch the leading tone (7), it creates for some interesting potential in its harmonic placement. It is also the least “defined” chord in terms of tonal area out of all the diatonic chords and can be found comfortably in the tonic, predominant, and dominant areas.
WHAT IS THE SUBMEDIANT?
SUBMEDIANT is the term we use to refer to the sixth scale degree and its accompanying chord (6 - 1 - 3). If the mediant is three above tonic, then the SUBmediant is three below tonic. Just like with the mediant, the submediant is the opposite quality of its home key - minor in major (vi) and major in minor (VI). This chord shares two scale degrees with tonic (I) and two scale degrees with subdominant (IV) so it is used most often as a predominant, a transition between tonic and predominant, or as a tonic substitution.
USE IN TONIC AREAS
EXPANDING THE TONIC
iii is a natural expansion of the tonic when following I as the bass arpeggiates up a third and scale degree 1 in the upper voices moves down to 7. In Peter, Paul & Mary’s “Puff the Magic Dragon,” this extension is comfortably embedded in the following chord progression:
Deceptive (Evaded) Cadence
vi is often used not only to expand the tonic, but flat out replace the tonic. When vi is subbed for I, this is called a TONIC SUBSTITUTION. This effect is found most often in a cadence type called a DECEPTIVE or EVADED CADENCE where instead of V resolving to I as your ear would expect, the music “deceives” the anticipation and resolves to minor instead. Hear this deceptive quality at 0:38 in The Beatle’s “Do You Want to Know a Secret.” This is most effective when authentic cadences (V - I) are established in earlier phrases.
USE IN PREDOMINANT AREAS
ASCENDING by thirds (III)
When the iii appears as part of an ascending bass arpeggiation (I - iii - V), it serves as the predominant between the tonic and dominant. Notice in the example that only one upper voice moves at a time.
Descending by thirds (vi)
When the vi appears as part of a descending bass arpeggiation (I - vi - IV), it serves as transitional/connective material between the tonic and a stronger predominant chord.
Descending by FIFTHS (vi)
A typical descending-by-fifths pattern from PD - D - T is the ii - V - I “turn around” pattern we learned about in Theory II. When adding another chord to the beginning, we see the emergence of the vi as in: vi - ii - V - I. In jazz, this progression is referred to as “Rhythm Changes” and was popularized in George Gershwin’s “I Got Rhythm.”
“PACHELBEL’S CANON” SEQUENCE (III + VI)
A final interesting progression combines both the iii and the vi into the predominant area by following the sequence of harmonic movement down a fourth then up a second: I - V - vi - iii - IV - I - IV - V. The progression is named after the popular “Canon in D” by Johann Pachelbel. Notice that the pattern is broken by the second IV appearing as the seventh chord in the pattern (which substitutes for a minor ii in the sequence).
“Canon in D” by Johann Pachelbel (1680)
