Polyrhythmic Pulse Modulation Or What The... !?
These exercises illustrate a concept I like to play around with that’s especially fun when soloing over a vamp. In Ex. 1 you’ll find a very simple groove based on a strong quarter-note pulse. As each of these quarter-notes is worth four sixteenths we can modulate the pulse to a note value that is worth only three sixteenths – dotted eighth notes. Ex. 2 shows the accelerated groove notated with the dotted eighths. Unfortunately it’s hideous to try and read.
Ex. 3 is the same rhythm written out with note values that allow you to see the separate quarter-note beat pulses. It’s quite a bit easier to read. You’ll also be able to see that the bass/snare/bass/snare pattern cycles every three beats. So the result is the groove is now a 4-over-3 polyrhythm against the original quarter-note pulse. That’s also why it takes three bars to completely cycle. Ex. 4 is a small variation of the same concept. Here I add another sixteenth in the pattern on the hi-hat. Each dotted eighth is played as an eighth and a sixteenth on the hi-hat.
DRUM! Music Editor Wally Schnalle is a drummer, composer, and teacher based in the San Francisco Bay Area, and has performed with Eddie Gale, Ernie Watts, and the San Francisco Symphony Orchestra.