Tritone Substitutions

Today I️ want to take what was discussed in the last blog II-V-I️ Alterations and build on that. So if you haven’t checked out last week’s blog, stop now and go back to that one first.

What is a Tritone?

A tritone is exactly what I️t sounds like. It’s a type of interval (the distance between two notes). More specifically, I️t is a distance of three whole tones from the starting note, hence the name TRI - Tone. For example, a tritone away from C is F#. One easy way of finding the tritone, if you’re familiar with the Nashville number system, is to think of the starting point as a root or tonic, then the tritone is the note in between the IV and V. It has a harsh, dissonant sound that is not commonly used in pop music, but more common in Jazz, Gospel, and Blues.

What is a substitution?

A substitution is an alternate chord that is used in place of the standard chord in a specific set of chord changes. There are different types of substitutions that can be used for different circumstances with endless combinations and possibilities to keep songs fresh and new.

So, to summarize, a Tritone substitution is a substituted chord, specifically a Tritone away from the original chord.

The Fine Print:

Now for the Nitty-Gritty. In order for Tritone Subs to work, you can’t simply play just any type of chord on that new Tritone note, there are some ground rules. Tritone Substitutions are typically used to replace the Dominant chord in a cadence. Or the “V” chord that leads to the resolution “I️” chord. You can also use tritone subs for other preceding chords, but the resolution should remain unchanged. The resolution is your anchor, which is what makes the substitutions really stand out. It's your point of reference.

And now for some examples.

Here we have a standard II-V-I progression in C major.

Below are a few examples of a few basic TriTone Substitutions:

Example 1:

First, let’s substitute the V chord. A tritone away from G, is Db. So this will be a chord built off of Db. Since we are resolving to C major, it makes sense to use dominant for this chord and it works well.

Example 2:

A subtle alteration of the first Example. Instead of making the Tritone Substitution of the V a dominant chord, we use a major sound. I chose specifically, Major 6 in order to create “Parallel Motion” (Where all of the individual notes move exactly the same distance to reach the next chord) between this chord and the final resolution of C Major 6.

Example 3:

Dual TriTone Substitutions. This time we will also substitute for the II chord. This creates a new 5th-Cycle-Motion between the first two chords. What we call a “Deceptive Cadence”. It’s a II-V progression that deceives our ears into thinking we may be in a completely different key for a moment. In this example, the tritone substitution for II (D) is Ab. I am using a minor quality to mirror the minor quality of the chord we are replacing. This is followed by the TriTone Substitution for the V (G) chord, which is Db. I am using dominant this time to complete the Deceptive Cadence. These two chords by themselves are a II-V in the key of Gb Major. But we still resolve to the Tonic (Root) of the key we are actually in, C Major.

Example 4:

Also using dual TriTone Substitutions here, but this time, I’ve altered the quality of these chords so that the first sub, Ab is now a dominant chord and the second sub, the Db is a major chord. This is another type of deceptive cadence, where the first chord is functioning like a V and the second chord is functioning like a I before the “Real” I (C). If you want to add another level of voice leading here, you can make the Db Major 7 chord a Db Major 6 chord instead, which revolves using parallel motion again down a half step to the C Major 6.

Example 5:

In this example, I am only substituting for the II chord. This creates a nice, half-step downward motion between the first two chords before resolving to the I.

Example 6:

In this last example, I am slightly altering Example 5, but making the first chord a Major 7 instead of a Dominant chord. This is for sonic purposes only. It gives a different color. It's kind of nice alternating between the major sound and dominant sound between these three chords.

The possibilities are endless! Please experiment on your own and let me know what you come up with! As always, I am available for further questions and further explanations if any of this stuff is hard to grasp. Let me know!

Happy TT-Subbing!