SUBSTITUTE ...
This month Richard Barrett changes a chord within a progression to showcase some interesting melodic ideas
The term tritone refers to an interval that spans three whole tones. For example, this could be: C to D, D to E then E to F#. However, another way of looking at it could be as an augmented 4th (C to F#) or a diminished 5th (C to G b). As you can see, these are all different names for one specific sound. Once we get into chord progressions and ‘diatonic speak’ such as II-V-I, you may well come across the term ‘tritone substitution’. All this actually means is that a chord within a progression (usually the V) has been exchanged for another with the root a tritone away.
Let’s explore this with a couple of examples. First, a jazzy II-V-I in C major would be Dm7-G7-Cmaj7. Then, if we move the G7 up a tritone/aug 4th/dim 5th, we will get a Db7. Now, the progression would be Dm7 ‐ Db7-Cmaj7, which can support many of the same melodic ideas but positions them in a different light. Why not get experimental and have a go at a Dm7 ‐ D bmaj7-Cmaj7 progession?
Example 1
If we took an Em-A7-D (II-V-I) progression and decided to jazz it up with 7ths and extensions, we might well start with this Em9 chord. The F# (9th) is our highest note. Imention this because the F# will be the highest note of one of our other examples, too.
Example 2
As the Vchord, the Ais the most likely candidate in our sights for substitution. Let’s make it
