Ever since that glorious moment when I strummed all six of the guitar’s open strings and realized I was playing an Em11 chord, I’ve known that the guitar is much more than the world’s coolest sounding instrument. It’s also one of music’s greatest compositional tools. This is because the guitar already has its own music built into it. Just bang on the thing, and, by virtue of its clever design—six tantalizing open strings hovering above a magical ladder of frets—you’re sure to find some inspiring sounds. And when you incorporate those primal, intuitive textures (specifically, the mesmerizing jangle of open strings) into more complex harmonic approaches, the guitar yields magnificent tapestries of sound that no other instrument can touch.
For example, many composers love the sustained common tone, because when two or more chords share one note in common, the resulting progression often sounds smoother than a Frank Sinatra pickup line. And common tones never sound more captivating than when they’re played as open strings on the guitar. Everybody and their grandma seems to favor either the top or bottom voice in a progression for the common tone, but in Ex. 1’s hypnotic series of arpeggiated chords, the common tone—the open B string—appears in a middle voice, which yields a refreshing sound. Dig how the open B—as if by magic—morphs from the 9 of Am(add9) into the #11 of F(add#11), into the anchor note in Cmaj7, and finally into the 3 of G. To more clearly hear how this common tone functions in the example, those guitarists who believe they can sing a note in tune—which, unfortunately, is just about all of us—may try singing a B while playing through the progression using basic, first-position chords (Am, F, C, and G).
Ex. 2 uses—gasp!—two open strings in the middle voices as common tones. And while this little ditty sounds great strummed as well as arpeggiated, I prefer the latter tactic—particularly because it provides a sly cheat: While plucking the open G and D strings, the fretting hand has time to jump to the next chord, further adding smoothness to the shifting harmonies.
Boldly going where many have gone before, Ex. 3 incorporates three common tones—two fretted and one open—above a moving bass voice. This is different from playing a bass line over a repeated chord because here, each new bass note affects a distinctly different harmony (i.e. chord) in the progression. Be forewarned: This technique generally pisses off bass players because it paints them into a musical corner, thus stealing their thunder. After you have composed the riff, be nice and let your faithful four-stringed friend play the low part.