Using Tritone Substitutions in Comping and Soloing

The tritone is the only interval invertible on itself – that is, the inverse of a tritone is also a tritone. This interval is also the flat fifth, or augmented forth (which is also the distance between the third and flat seventh of a dominant seven chord.)

The concept of a tritone substitution is simple and very easy to visualize using the chord shells I taught a while back.

The basic idea says that

C7: C E G Bb

can sub for

F#7: F# A#(Bb) C# E

The reasoning is, that the third and the seventh provide the most important tones of the given chords, and C7 and F#7 contain the same third and seventh (only inversed).

Also notice that the roots end up being a tritone apart.

Application for Comping

Let's take autumn leaves for example, and add some substitutions in

Am7 | D7 | Gmaj7 | Cmaj7

Create the first line, however lets substitute D7 with the dominant seven chord a tritone away, which would be Ab7.

Am7 | Ab7 | Gmaj7 | Cmaj7

We now have some cool chromaticism happening in the first three measures.

We can also take the last line of a standard twelve bar blues and create chromaticism: (in C, sub the C chord for it's tritone F#)

G7 | F7 | F#7 | G7 |

Application for Soloing

Let's take a generic line for a ii-V-I progression

Now let's move the notes over the G7 up a tritone, implying a C#7 chord in it's place (I've changed the last note of the bar to make it fit into the line better.

This adds a good chunk of dissonance to your soloing, and can be used any time you see a dominate seven chord (meaning you can go crazy with it during a 12 bar blues.