Example 5 Chord Substitutions and Slash Chords

In this C major-based example, we are dealing with two concepts - substitution – which we’ve already touched upon – and slash chords. Slash chords are similar to the inverted chords of example 1, but slash chord is a more general term. Whilst the inversion must have a chord tone in the bass, a slash chord can use any note in the bass of any chord. So go ahead and experiment with putting various notes under every chord you can think of. I love the sound of a major chord with a minor 7th in the bass as it occurs in bar 2 and 4 (C/Bb and F/Eb). You can see bars 6 and 8 as tritone substitutions. If you imagine bars 5- 8 being based on a standard I-VI- II-V progression, and the VI (A7) and V (G7) chords are altered dominant chords (#5, b9, #11), you will see that these contain much the same notes as the chords they have been substituted with (Eb9 and Db9). In addition, notice how you always achieve a smooth chromatic bass movement when using tritone substitution in this fashion. Bar 10 is another cool move, where we turn the III chord, which would usually be minor, into a dominant; this leads nicely into the next chord (F7), giving it a bluesy feel in the process. You can hear a great example of this particular move in (Sittin’ On) The Dock Of The Bay. Bar 12 has another textbook example of tritone substitution (Db13), before venturing into slash chord territory again - as you might hear it on a Joe Satriani track - before ending on the thoughtful G/C, which you could also see as a simplified version of a Cmaj9.