Modal interchange (also known as modal mixture) is the technique of borrowing chords from parallel modes or scales—modes that share the same tonic but differ in their intervallic structure. This practice enriches harmonic vocabulary, enabling unexpected and sophisticated chord progressions that bring fresh colors and emotional nuances to music.
- Occurs between parallel modes (e.g., C major and C minor)
- Adds new chords unavailable in the original key's diatonic scale
- Provides surprising harmonic shifts and emotional depth
- Common in many genres, especially pop, rock, jazz, and film music
Modal interchange borrows chords from parallel modes.
How Modal Interchange Works
The major scale (Ionian mode) defines a specific set of diatonic chords. By contrast, its parallel modes (like natural minor, Dorian, Phrygian, etc.) replace some scale degrees with different intervals, producing unique chords that can be "borrowed" to add variety.
For example, in C major, the diatonic triads are:
| Scale Degree | Chord | Notes |
|---|---|---|
| I | C | C-E-G |
| ii | Dm | D-F-A |
| iii | Em | E-G-B |
| IV | F | F-A-C |
| V | G | G-B-D |
| vi | Am | A-C-E |
| vii° | Bdim | B-D-F |
From the parallel C minor (natural minor) mode, some chords change to:
| Degree | Minor Mode Chord | Notes | Major Mode Equivalent |
|---|---|---|---|
| i | Cm | C-E♭-G | I (C) |
| iv | Fm | F-A♭-C | IV (F) |
| V | Gm (instead of G) | G-B♭-D | V (G) |
| VI | A♭ (major) | A♭-C-E♭ | vi (Am) |
| VII | B♭ (major) | B♭-D-F | vii° (Bdim) |
By borrowing iv (Fm), VI (A♭), or VII (B♭) from C minor, a composer enriches C major's palette.
- Original key: Only diatonic chords from its scale
- Parallel mode: Offers new chord options with altered tones
- Borrowed chords: Usually bring distinctive colors like melancholy (minor iv in major key) or warmth (major VI in major key)
Modal interchange adds nuance, expands harmony, and creates surprises.
Common borrowed chords include minor iv, major VI, and major VII from the parallel minor.
Examples of Modal Interchange
Example 1: Borrowing iv in a major key
| Measure | Chord Progression | Notes (C context) |
|---|---|---|
| 1 | C (I) | C - E - G |
| 2 | Fm (iv borrowed) | F - A♭ - C |
| 3 | C (I) | C - E - G |
Here, Fm replaces the usual diatonic IV chord (F major), adding a darker, more emotional tone.
Example 2: Borrowing VI and VII
| Measure | Chord Progression | Notes (C context) |
|---|---|---|
| 1 | C (I) | C - E - G |
| 2 | A♭ (VI borrowed) | A♭ - C - E♭ |
| 3 | B♭ (VII borrowed) | B♭ - D - F |
| 4 | C (I) | C - E - G |
The A♭ and B♭ chords (from C minor) bring richness and a sense of departure before resolving back to the home chord.
Borrowing iv introduces a darker emotional tone.
Common modal interchange chords are iv, VI, and VII.
Modal interchange is popular in pop, rock, jazz, and film music.
The natural minor mode is most commonly borrowed from when applying modal interchange to a major key.
Typical modal interchange chords from parallel minor are iv, VI, and VII.
Conclusion
Modal interchange is a potent tool for composers and arrangers, offering a means to sidestep predictability and enrich harmonic storytelling by blurring the boundaries between "modes."
- Chords are borrowed from parallel modes to add color and emotion.
- Common borrowed chords in major keys come from the parallel minor (e.g., iv, VI, VII).
- This technique is widely used across many musical genres for creative effect.
Modal interchange borrows chords from parallel modes.
Modal interchange adds colors, emotional range, and harmonic interest, but does not simplify progressions.
Common borrowed chords include iv, VI, and VII from the parallel minor.