VI. Jazz
Substitutions
Megan Lavengood
Key Takeaways
This chapter discusses methods for altering chord progressions through chord substitution.
- A progression that moves by fifth can substitute the first chord with the dominant chord that shares the same root. This makes the first chord an applied chord to the second chord.
- Mode mixture is when a piece in a major key uses chords borrowed from the parallel minor key (or vice versa, though this is less common).
- In jazz, the most common mixture chords are substituting ii∅7 for ii7 and adding ♭9 to a V7 chord.
- The most common mixture chords, including ii∅7 and V7♭9, substitute le for la [latex](\downarrow\hat6[/latex] for [latex]\natural\hat6)[/latex].
- Tritone substitutions replace a dominant chord with another dominant chord a tritone away. The name refers both to the interval between the original and substituted chords and to the fact that the two chords share the same tritone.
Creating new interpretations of old favorite tunes is one of the cornerstones of jazz, and because of this, the concept of chord substitutions is extremely important. Substitutions provide a way for performers and arrangers to put a new spin on more well-trodden harmonic progressions. This chapter uses the turnaround as a basic progression to be altered, but these substitutions can be applied anywhere in a harmonic progression.
Applied Chords as Substitutions
As discussed in the Tonicization chapter, an applied chord can be productively related to the diatonic chord with which it shares a root note.
Because root motion by fifth is extremely common in jazz, there are many opportunities for performers to simply substitute the first chord in a fifth-wise chord progression with the dominant seventh built on the same root. One especially common place where this is implemented is in the turnaround, where, because each chord is related to the next by fifth, a chain of applied V7s is a common variant ( ).
Mode Mixture
“All of You” by Cole Porter is a composition that has mode mixture built into it. Listen to this recording by Ella Fitzgerald (transcribed in ), conveniently in C major, and observe how the alternation between A♮ (la, [latex]\hat6[/latex]) and A♭ (le, [latex]\downarrow\hat6[/latex]) catches the ear and imbues a sense of sentimentality in the song. A♭ here can be understood as being borrowed from the parallel minor (C minor), a practice known as mode mixture.
Many songs, like “All of You,” have mixture built into their chord structure. But mixture chords can also work as improvised substitutions: a chord within a diatonic chord progression can be substituted with its minor-mode variant to produce a color change that won’t change the overall function of the chord. A mixture substitution works best when the scale degree being inflected is la [latex](\hat6)[/latex], and is therefore being transformed into le [latex](\downarrow\hat6)[/latex]. As an example, consider the turnaround in
: instead of a diatonic version