Jazz is packed with harmonies that can sound foreign to those not in the know. But with the knowledge of a few basic principles, it all starts to make sense. What jazz players are often doing is reharmonizing basic chord progressions common to different popular styles—progressions that you likely already know—and using substitute chords to add color and complexity.
If you’re not a jazz musician, learning jazz harmony might not seem particularly compelling. But whether you play folk, rock, country blues, Celtic fingerstyle, or anything else, knowing how jazz harmony works and borrowing from it now and then can only make your music more interesting, while enhancing your musicianship. With that in mind, dig in to this primer on various harmonic techniques.
In order to understand chord substitution, you should first be familiar with basic diatonic harmony—chords formed from the notes of a given scale. Take a moment to study Ex. 1, which shows the triads (three-note chords) built from the notes of the C-major scale and Ex. 2, depicting seventh chords derived from the scale. You’ll be using these Roman numerals later in this workout; note that uppercase numerals represent major chords and lowercase minor chords.
Now let’s get into some substitutions. Ex. 3 is a basic progression in the key of C containing the I, IV, and V chords (C, F, and G7).
To make the progression more interesting, in Ex. 4, on beat 3 of bar 1, you’ll substitute the C chord with a C7. On beat 3 of the next bar, in place of the F major chord, you’ll play an F minor, lending an interesting harmonic color.
In Ex. 5, throw some bass notes other than roots into the mix for even more harmonic flavor. For instance, on beat 3 of bar 1, play the C7 chord’s third, E, as the lowest note, leading smoothly up to the F in the following measure. Now, to hear how your I–IV–V progression has been transformed over the last few exercises, compare Ex. 5 to Ex. 3.
This week you’ll treat a I–vi–ii–V progression, the bedrock of so many jazz and popular songs, to a variety of reharmonizations. Begin with the basic progression, shown in the key of C major in Ex. 6. Next, in Ex. 7, replace the I chord (Cmaj7) with the iii (Em7). In Ex. 8, you’ll use another common substitution—the V7 of ii. Instead of playing the vi chord Am, which occurs naturally in C major, you’ll play an A7, the V7 of Dm7.
Combine the substitutions in Ex. 7 and Ex. 8 to arrive at Ex. 9, which creates a pair of descending ii–V progressions (Em7–A7 and Dm7–G7)—an essential jazz move. Turn the minor-seventh chords into dominant sevenths (Ex. 10) and you’ll have a series of seventh chords traveling counterclockwise on the circle of fifths. Astute readers will know this particular sequence of chords as that used in the bridge of “rhythm changes”—named after the Gershwin tune “I Got Rhythm,” one of the most common forms in jazz.
In Ex. 11 we substitute the A7 and G7 chords with EH7 and DH7. This move is known as tritone substitution—the root of the EH7 chord (EH) is a tritone, or three steps from that of the A7 chord, and ditto for the roots of the DH7 and G7 chords. If that sounds confusing, spend a minute with Ex. 12, which gets into the concept more deeply. In bar 1 you’ll find a G7 chord and its tritone substitution, DH7. As demonstrated in the second bar, these two chords have two notes in common—F, which is the seventh of G7 and the third of DH7, and B/Cb, which is the third of G7 and the flatted seventh of DH7. Put it all together by adding the roots (G and DH) in the third measure.
For good measure, subject the original I–vi–ii–V to one last variation. As directed in Ex. 13, keep the tritone sub on beat 3 of each measure, but revert to the I and ii chords (Cmaj7 and Dm7). Note the smoothly descending bass line (EH–D– Db) between the last three chords.
In some instances, you can think of complex-sounding chords in simple terms: as triads over bass notes. For example, the first chord in bar 1 of Ex. 14 is typically labeled as Cmaj9, but you can get the same sound by playing a G triad (G B D) over the note C, as the next voicing illustrates. The second measure shows you how to use the G/C chord in a ii–V–I progression—another building block of jazz—in the key of C.
You can also think of a minor-seventh chord as a triad over a bass note. Bar 1, beat 1 of Ex. 15 shows a typical Dm7 chord in fifth position, while the chord on beat 3 shows that a Dm7 chord is equivalent to an F triad (F A C). Try plugging this chord into the ii–V–I progression, as shown in bar 2.
If you’re not a jazzer, then you might not know what to do if someone asks you to play, say, a 13H9 chord. But this altered dominant chord, too, can be played as a triad. The first bar of Ex. 16 shows what happens when you play an E triad over a G bass note (with the addition of the G chord’s flatted seventh, F), and the second bar places the resulting chord in the ii–V–I progression. Notice how between the first two chords the F triad on strings 1–3 moves down neatly by half step to the E triad.
This week we’ll explore various ways to spice up single chords, rather than chords in progression. If you’re faced with a dominant seventh chord, for instance, you might flatten its fifth or raise it, as shown in Ex. 17, which creates a nice dynamic tension in the sound. In Ex. 18, do the same with an Fmaj7 chord for new harmonic colors.
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Another way of making a chord more interesting is to move one of its voices around in what’s known in jazz as a line cliché or chromatic cliché. In Ex. 19, start with a plain old C chord, then move its second-highest voice, on string 3, around by half step to form a C–Caug–C6–Caug progression. Ex. 20 is based on the same idea, but the note that moves around is the highest voice.
The same concept is illustrated on a Dm chord in Ex. 21, where movement on string 2 results in a colorful Dm–Dm(maj7)–Dm7–Dm6 progression. In Ex. 22, the notes on string 3 are shifted around to create a Dm–BH/D–Ddim7–BH/D move, recalling the James Bond theme.
Once you’ve absorbed all the chord-substitution and reharmonization ideas in this workout, try it again in other keys. Take the concepts, apply them to your own music, and you’ll be playing with new depth and excitement.