Borrowed chords: adding color from the parallel minor

A borrowed chord takes its notes from the parallel minor, the minor key with the same tonic. In C major, Fm, Ab, and Bb come from C minor: Fm resolves to C, Ab moves to Bb or to G, and Bb resolves to C.

What C minor contributes

C natural minor is C, D, Eb, F, G, Ab, Bb. Its triads are Cm (C Eb G), Ddim (D F Ab), Eb (Eb G Bb), Fm (F Ab C), Gm (G Bb D), Ab (Ab C Eb), and Bb (Bb D F). C major's own triads are C (C E G), Dm (D F A), Em (E G B), F (F A C), G (G B D), Am (A C E), and Bdim (B D F). Borrowing means the key stays C major while you play a chord from that C minor list.

iv resolves to I

F major is F A C. Fm is F Ab C, labeled iv when the key is C major. Play C, F, Fm, C and move one voice from A to Ab to G. A is the third of F. Ab is the third of Fm. G is the fifth of C (C E G).

Play C, Fm, C. Ab falls a half step to G. That cadence is a minor plagal, iv to I, the minor form of the plagal cadence in harmonic function.

bVI moves to bVII, or down to V

Ab is Ab C Eb, labeled bVI in C major. One resolution climbs by step through bVII into the tonic. Play C, Ab, Bb, C.

Ab (Ab C Eb) goes to Bb (Bb D F) with each note up a whole step: Ab to Bb, C to D, Eb to F. Bb goes to C (C E G) the same way: Bb to C, D to E, F to G.

The other resolution steps down into G, the dominant. Play Ab as Ab3 C4 Eb4, then G as G3 B3 D4. Ab falls to G, C falls to B, and Eb falls to D, each by a half step. Then play C, and B in that G chord rises to C. The four chords are C, Ab, G, C.

bVII resolves to I

Bb is Bb D F, labeled bVII. Play C, Bb, C. From Bb to the final C, each note rises a whole step: Bb to C, D to E, F to G.

Bb7 adds Ab, spelled Bb D F Ab. D and Ab are a tritone, the third and the seventh. D rises a whole step to E. Ab falls a half step to G. Play:

Bb7   Bb2  D3  F3  Ab4
C     C3   E3  G3  G4

The second chord is C major, C E G, with G played twice. Ab4 falls to G4, D3 rises to E3, Bb2 rises to C3, and F3 rises to G3. Cmaj7 is C E G B. Add B3 below that G4: B3 is a half step under middle C (C4), and the resolution notes are then C3, E3, G3, B3, and G4.

bIII steps up to IV

Eb is Eb G Bb, labeled bIII. It shares G with the C major triad C E G. A common next chord is F, the major IV. Play Eb as Eb3 G3 Bb3, then F as F3 A3 C4. Eb rises to F, G rises to A, and Bb rises to C. Each note moves up a whole step. Play C, Eb, F, C: C E G, then Eb G Bb, then F A C, then C E G.

Eb can also move to Ab, bVI. Play C, Eb, Ab, Bb, C. Eb (Eb G Bb) moves to Ab (Ab C Eb), and Bb (Bb D F) resolves to C (C E G).

The half-diminished ii resolves to V

Dm7 in C major is D F A C. The borrowed half-diminished chord is Dm7b5, spelled D F Ab C. The changed note is A to Ab, and Ab belongs to C minor. Dm7b5 still prepares G7. Play:

Dm7b5  D3  F3  Ab3  C4
G7     D3  F3  G3   B3
Cmaj7  C3  E3  G3   B3

Ab3 falls a half step to G3. C4 falls a half step to B3. F3 holds into G7, then falls a half step to E3. D3 holds into G7 as the fifth of G B D F, then falls a whole step to C3. G3 holds into Cmaj7. B3 holds into Cmaj7, where it is the seventh of C E G B. The diatonic voicing uses A3, and that A3 steps down a whole step to G3. The rising bass and the inversions of Dm7, G7, Cmaj7 are in voice leading.

One loop with two resolutions

Play C, Fm, C, Ab, Bb, C.

The first C is C E G, the tonic. Fm is F Ab C, and it resolves when the next C arrives and Ab has fallen to G. Ab is Ab C Eb, and it moves to Bb (Bb D F). Bb resolves to the last C, with Bb, D, and F each rising a whole step to C, E, and G.

Drag the chord onto a C major timeline

Leave KEY on the Dashboard at C. Use EDIT VOICING on a PALETTE voicing button and set its chord to Fm, Ab, or Bb. Drag that button onto the progression timeline. Switch the block display format to letter and read Fm, Ab, or Bb. Open Listen for chord & scale, hold F, Ab, and C, choose Fm from the candidates, and APPLY. The button stores F, Ab, and C.

Generate a C major draft, then replace one diatonic block with one of these chords. The generate, delete, and replace steps are in the chord progression generator.

Put Fm, Ab, and Bb on the timeline and play C, Fm, C, Ab, Bb, C. Then play Dm7b5, G7, Cmaj7 beside Dm7, G7, Cmaj7, using the fingerings in voice leading.