Tritone Substitution, the ultimate guide for Jazz Piano
Tritone Substitution Explained, Once & For All
What is Tritone Substitution?
Tritone substitution is a reharmonization technique used often by jazz musicians.
‘Reharmonization’ means to change a song’s chords to something new, and ‘Tritone Sub’ is probably the best known reharmonization technique there is.
How Tritone Substitution Works
Tritone substitution is applied to dominant 7 chords only (e.g. C7, F7, Bb7, etc). It’s where you take a V7 chord and you transpose it up a tritone.
‘Tritone’ is an interval - it literally means ‘three tones’. So if you count up from C by three whole-tones you’ll reach F# - and this distance is a tritone:
IMAGE - C counting up 3 whole-tones to F# (tritone)
NOTE: The tritone interval goes by two other names - ‘augmented 4th’ (for when it’s spelled C - F#), and ‘diminished 5th’ (for when it’s spelled C - Gb). But the term ‘tritone’ is always accurate, regardless of spelling - which is why many musicians use the term ‘tritone’ for all situations involving this interval.
So let’s say you see C7 in the chord sheet - that means you can use tritone substitution and transpose C7 up a tritone - which brings you to Gb7:
IMAGE - C7 becomes Gb7
Tritone Sub on the 2-5-1
Most V7 chords you’ll encounter will be the middle chord of a 2-5-1 progression.
A 2-5-1 in C major would look like this:
IMAGE - sheet music: 2-5-1 in C major
D min 7 - G7 - C maj 7
Now let’s apply tritone sub to the V7 chord - which chord will we play instead of G7?
That’s right - Db7 (or you might have said C#7, which is also correct).
So here’s how you would play a 2-5-1 with tritone sub added:
IMAGE - sheet music: 2-bII-1 in C major. Tritone sub.
Notice that we now get a chromatic moving bass line that plays D - Db - C.
In a way, playing the 2-5-1 with tritone substitution is SIMPLER than playing a 2-5-1 without. You simply count down in half-steps and build the appropriate chord types - rather than having to jump up a 4th and then down a 5th (D G C).
Why Does Tritone Sub Work?
When you transpose a V7 chord up a tritone, the new chord contains two of the same notes as before, and two of the notes change - just slightly.
So let’s look at C7 and Gb7 (both are the tritone substitution of each other):
IMAGE - sheet music: C7 / Gb 7 = 2 notes same, 2 notes different
C7 and Gb7 both contain E and Bb (the 3rd and 7th of C7, or the 7th and 3rd of Gb7).
But C7’s C and G now change to Db and Gb - just a half-step change in opposite directions.
This means that the two most important chord tones - the 3rd and 7th, which tell your ear what the chord is - stay the same.
But then we get an altered sound which comes from the sharpening and flattening of the root and 5th.
When you Change the Chord, you also Change the Scale
When you change C7 to Gb7, you’ll sometimes need to tweak the notes in the song’s melody - that is, if they clash with the new chord and its implied scale.
What scale should we play over the reharmonized V7 chord?
I suggest you use the lydian-dominant scale. So over C7, you would play notes from C lydian-dominant scale:
IMAGE - C Lydian-Dominant scale over C7
Let’s see how this would look over a 2-5-1 progression in C major:
For the ii chord and I chord (D min 7 and C maj 7), let’s play notes from C major scale.
But for the bII7 chord (Db7), we need to play notes from Db lydian-dominant scale:
IMAGE - sheet music: Dm7 Db7 C maj 7 - with scales written above
So let’s say the original melody plays an A over the G7 chord. Now we’ll have to tweak this note - we could either flatten it (Ab), or sharpen it (Bb).
Or let’s say the original melody plays a D over the G7 chord. Now we’ll have to flatten it (Db), or sharpen it (Eb).
It’s up to you whether you flatten or sharpen a note - it depends on the melody, so just try both and see which sounds best. All you’re doing is removing the ‘wrong note’ (the note that no longer fits with the new scale) and nudging it sideways to a right note - which will always be a half-step either side of a ‘wrong note’.
In most cases I find myself flattening the original note to fit with the new scale.
Practice Tip
Choose 3 songs from your real book and apply tritone substitution to them. Look out for V7 chords and practice transposing them up by a tritone. Then tweak any melody notes so that they fit with the new scale.
Recommended songs: Misty, Cry Me A River, Autumn Leaves, Fly Me To The Moon, Ladybird.
Tritone Substitution chord voicings
To get tritone substitution to sound really sophisticated, you need to use the right chord voicings.
I’ve notated some of my favorite chord voicing patterns which I use for Tritone Substitution and the 2-5-1. Click here to download (free).
Tritone Substitution Video Tutorial
To hear tritone substitution, watch my complete tritone substitution video tutorial.
Click here to watch Tritone Substitution Explained (https://jazztutorial.com/membership/tritone-substitution)
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About the Author
Julian Bradley is a jazz pianist and music educator from the U.K. He has a masters degree in music from Bristol University, and has played with and composed for a variety of big bands.
Julian runs the popular Jazz Tutorial YouTube channel and writes educational jazz lessons at JazzTutorial.com
