One of the most fascinating discoveries I made during my first few lessons with my mentor, Joe Diorio—a true master of outside playing—was that a lot of the really free comping sounds introduced to jazz by pianists such as McCoy Tyner and Herbie Hancock were based on a simple 20th-century classical music device known as parallel motion. Based on the C Dorian mode, Ex. 1—a series of stacked-fourth grips that you can apply on standards such as “Footprints” and “Mr. PC”—provides an introduction to this rich and sophisticated sound; a sound generated by moving an unchanging harmonic cluster up and down in pitch.
Taking things a step further, Ex. 2 features one of the most common chord structures used by modern jazz pianists for outside comping—the “So What” voicing, as it’s sometimes called in jazz jargon. This grip stacks two perfect fourths and tops them with a major third. Played over an Fm7 “Love Supreme”-type groove, the voicing offers such flexibility that when we move the shape around freely (while concentrating on achieving a singable melody with the top voice) it creates a truly multi-dimensional comping sound. The lower notes in each voicing may go entirely outside the key while a strong melody on the top voice keeps the whole thing sounding lyrical. (It’s interesting to note that whenever you comp this way it makes the soloist sound outside even if they’re playing entirely inside the tonality.)
Another captivating voicing that is well-suited for parallel comping is the maj7b5. In Ex. 3 you’ll see this harmony shifted up and down the neck and superimposed over a Dm backdrop. (It jumps to a higher set of strings—and an easier fingering—at bar 6.) One way to feel more comfortable with this type of comping is to momentarily forget about the root names, etc., and just go for the right sound.
While these mesmerizing modern harmonic tapestries can be tricky to play on the piano, they’re actually surprisingly easy to execute on the guitar—just move the given grip up and down the neck, refingering for different string sets if necessary. Today, guitarists such as Bill Frisell, Mike Stern, John Scofield, Jim Hall, and Pat Metheny make extensive use of parallel motion. The harmonically ambiguous nature of parallel voicings can easily sound vague when played without enough rhythmic propulsion and confidence, so I recommend practicing these sequences until they become second nature. Perhaps the best way to learn the art of modal playing is listening to this kind of music with concentrated attention, playing along with great recordings. Most of all, take inspiration from the modal pioneers who risked their careers and fan bases in pursuit of these new sounds and don’t be afraid to go out on a musical limb yourself.