Jazz Guitar - How to use Tritone Substitutions in a Blues context
Dang Good Joe Pass CD's
What is a tritone substitution?
Chord substitutions are a good way to add a bit of variation to your playing, and are very compatible with keeping a walking bass line below your chords. These two elements are key in developing a good jazz guitar sound. Great solo jazz guitar players, like my personal favorite, Joe Pass, used these extensively in his improvisation. All that a chord substitution implies is to change the chord you're "supposed" to play, by a different, somehow related chord. A real simple one to get you started is the tritone substitution.
I'll show you chord patterns that use these as we get down there later, but first let me tell you what a tritone substitution is. The tritone substitution most often involves a dominant 7th chord, and playing another dominant chord a tritone interval away from your original chord. A tritone is an interval composed of three whole-steps, and is just a half-step short of a perfect fifth. An easy way to visualize the tritone interval on guitar is to locate the perfect fifth of your tone, play a half-step (one fret) below that note.
A tritone substitution is done by locating the note that is a tritone interval away from the root of the chord that's written, and using that note as a root for your substituted chord. You will want to use a dominant 7 chord, or related (altered) forms like 9's, 13's, b5, #5, #9, etc. You can use this in blues, ii-V-I's of all kinds, pretty much anytime you see a dominant chord, you can play around with the substitution.
For example, if you read Dm7-G7-C (a ii-V7-I ), use a tritone substitution on the G7, and replace it with Db7. You will get: Dm7-Db7-C. The bass line descends chromatically from D to the root C, and sounds very smooth. Play around with the different altered versions of Db7. Db7b5 is convenient and cool, because it's actually the same as G7b5.
Tritone Substitution in a 12-bar blues
Once you're familiar with using the tritone substitution, try it on a 12-bar blues. If you're not familiar already with how to play the blues, I've also included below the chords you would need to play for a basic blues. I suggest get very familiar with the basic format, inside and out, before you use substitutions on it. Don't try to learn seventy-twelve things at the same time, you won't learn anything.
The advantage of using tritone substitutions in the blues context is that a lot of dominant chords are used in blues. Therefore, you can substitute in pretty much every bar, and it creates a very cool flowing sound. Check it out: (click on the images to zoom in! )
Chords in order of appearance:
Basic 12-Bar blues
12-Bar Blues with some tritone substitutions
Will be posting more jazz guitar tips and tricks shortly!