Chord-melody style, as its name implies, is a jazz guitar solo style that incorporates both the melody and harmony (chords) of a song. When you learn to play a chord-melody style, you can jazz up an existing non-jazz song.
Although the melody of the song is usually played straight (as composed), the performer changes the chords from traditional ones to jazz versions. These jazz chords, when they take the place of straight chords, are called substitutions. You can hear this style of playing in the music of such jazz greats as Johnny Smith, Jim Hall, and Joe Pass.
Although playing a written-out chord-melody solo isn’t especially difficult, creating one yourself (which is what jazz guitarists do) is no easy task. For starters, you need to know how to harmonize (put chords underneath) a melody; then you need to know how to apply chord substitutions.
These skills enter the realm of composing and arranging and can get quite involved. Fortunately, there's a way to sound like you're creating a chord-melody solo without doing all the actual arranging.
Making substitutions
Substitutions are jazzy chords that you use in place of straight chords. These chords come in one of two general forms:
Same root: Sometimes you substitute a chord with the same root, but using an extended version or chromatic alteration. For example, if the chord progression of the song starts with C and goes to A7, you might substitute Cmaj7 and A7b9, just to make it sound jazzy.
Different root: Other times, you can substitute chords that don’t even have the same root. Instead, the substitute chord may have other notes in common with the original. Taking the same example, instead of playing C and A7, you might play something like C6/9 and Eb7, because A7 and Eb7 have two notes in common (C#/Db and G).
There are countless possible chord substitutions you can make, and it can take years of playing jazz to develop an intuitive feel for knowing which chords can substitute where.
Faking it with three chords
Instead of learning hundreds of substitutions, try faking a chord-melody solo by using three simple chords. Look again at the first three movable chord shapes in the following figure: the outside voicings for m7, º7 (diminished seven), and 6/9. Because these chords have a somewhat ambiguous sound, they usually won’t sound wrong no matter where you play them, or what order you put them in: They just sound jazzy.
You can stick with one chord for a while, moving it to different frets — sliding up or down one fret at a time sounds cool. Or you can switch freely among the chords, playing them at various frets. Make up the rhythm as you go.
The following figure is an example of how to fake a jazz chord-melody solo using these three chords.
