19b Discussion - Mediant harmony and Simplified Voice-leading Intervals

Mediant Mania

“What is mediant harmony?”

• Chordal motion that involves root movement by thirds

“Why use mediant harmony?”

• It’s a way to move to distant keys in very smooth ways
• It allows composers to have smooth voice leading while using interesting harmony

Ex: Festive Overture opening

Simplified Voice-leading Intervals (SVI)

• This is a framework for measuring the amount of distance that voices move between chords
• You measure this by counting how many half steps each voice moves from one chord to the next, then totaling it up
• For example, a G major triad to a C major triad has an SVI value of 3

“Which chords have the lowest SVI?”

• The ones that share two common tones.
• With mediant harmony, there is always some sharing of common tones, which is why we say the voice-leading is so smooth - because there is very little motion.

In a tonal analysis you can use SVI as a way to explain motion between chords. However, this can only be used if the music is actually written in a way where the notes are moving smoothly to each other. The chords cannot merely have a theoretically smooth relationship.

• You can label this in your analysis by writing “SVI: _” between the roman numerals

SVI In C Major and Parallel Minor

1. C to Dm - SVI:5

2. C to Do - SVI:4

3. C to Eb - SVI:3

4. C to Em - SVI:1

5. C to Fm - SVI:2

6. C to F - SVI:3

7. C to Gm - SVI:4

8. C to G - SVI:3

9. C to Ab - SVI:2

10. C to Am - SVI:2

11. C to Bb - SVI:5

12. C to Bo - SVI:4

We are left with (in C) Eb, Em, Ab, Am.

We have 4 more mediant harmony chords, and they come from changing the quality of the previous chords.

• Ebm, E, Abm, A.

In total we have 4 chromatic mediant chords (Ebm, Eb, Em, E) and 4 chromatic submediant chords (Abm, Ab, Am, A).

Diatonic mediants: the two mediants that are in the key.

• In C major, Em and Am.

• your diatonic mediants always have 2 common tones and opposite chord qualities.

Chromatic mediants: the 4 mediants that are borrowed from the parallel minor and the opposite chord quality of the diatonic mediants.

• In C major, Eb, Ab, E, and A.

• Eb and Ab are from the parallel minor while the E and A are opposite chord qualities of diatonic mediants.

Doubly chromatic mediants: the 2 mediants that are not in the key, but are the opposite chord qualities of the parallel minor mediants.

• In C major, Ebm and Abm.

You find the first 4 mediants by using the diatonic and chromatic mediants (the 2 from major and 2 from the parallel minor).