Harmony II: substitution and reharmonisation
Go beyond the diatonic chords of a key: secondary dominants and their related ii chords, tritone substitution, diminished passing harmony, borrowed chords, the Coltrane major-third cycle, and a complete method for reharmonising a melody.
- Find the five secondary dominants of any major key, insert the related ii chord in front of each, and hear them in standards
- Substitute any dominant with the dominant a tritone away, voice-lead the result, and play turnarounds with chromatic bass lines
- Use diminished seventh chords as passing, auxiliary and dominant-function chords, and recognise the four dominants hidden inside each one
- Borrow chords from the parallel minor (iv, bVImaj7, bVII7, iiø7), play the backdoor progression and the minor plagal cadence in all keys
- Play the major-third cycle of Coltrane changes and the Countdown-style substitution over a ii–V–I at a slow tempo in several keys
- Reharmonise an eight-bar melody three different ways and explain every substitution
Modules 2 and 3 gave you the diatonic chords of a key and the ii–V–I that connects them. Almost everything else on a chart is a departure from those seven chords, and almost every departure can be explained by a handful of devices: a dominant that points at a chord other than the tonic, a dominant replaced by the one a tritone away, a diminished chord slipped between two diatonic chords, a chord borrowed from the parallel minor, or a chain of keys a major third apart. This module takes each device in turn, shows you how to voice it with the drop-2, drop-3 and shell shapes from Modules 4 and 8, how to hear it, and where it lives in the standard repertoire. The last lesson puts all of it to work on an original melody, because reharmonisation is where harmony stops being analysis and becomes something you play. Work through the lessons in order; each one assumes the vocabulary of the one before.