Rhythm Workshop: Everything You Need to Know About 15/8 Time

15/8's lopsided combinations of eights and sevens, and its divisibility by both five and three, allow for some very cool subdivisions and grooves.
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As with any odd meter, 1 5 /8, which entails 15 eighth-notes per measure as shown in Ex. 1, cannot be divided in half, but its lopsided combinations of eights and sevens, and its divisibility by both five and three, allow for some very cool subdivisions and grooves. In fact, the meter’s sheer amount of beats per measure necessitates subdividing just to keep track of its basic pulse.

We begin with the obvious 8+7 and 7+8 eighth-note divisions notated in Examples 2a and 2b. The former beams together two sets of four eighth-notes for an 8/8 grouping (essentially a bar of 4/4), followed by four- and three-note groups for the 7/8 division, while the latter reverses this strategy. Establish a comfortable tempo and tap your foot in accordance with the written accents in each example, noting how you must double-up your taps when crossing from sevens to eights. The overall effect is a bar of 4/4, followed by a bar of 7/8, or vice versa, and Examples 2c and 2d illustrate how both figures can be rewritten as such.

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Things get even more interesting when we subdivide a measure of 15/8 into the three five-note groups depicted in Ex. 3a. Count this one as you would three consecutive bars of 5/8 by doubling up your foot taps every fifth note. Ex. 3b reverses the 3x5/8 division to 5x3/8. This creates a triplet feel with a dotted-quarter-note pulse, making it ripe for a 15/8 shuffle—just omit the middle eighth in each three-note set— or further sixteenth-note divisions.

Our first real-life app (Ex. 4), which comes courtesy of the JB’s (Jeff Beck and Jennifer Batten), demonstrates the 8+7 grouping from Ex. 2a reinterpreted as Ex. 2c’s two-bar 4/4-plus-7/8 division. Here, we’ve got a busy, open-A-based single-note figure (played with a swing-sixteenth feel) that utilizes nearly every sixteenth note in both measures, sustaining or omitting only three sixteenth hits in bar 1 and two in bar 2 to create some funky syncopations. In fact, the only differences in the 7/8 measure are the omission of bar 1’s second (tied) C— the missing eighth note—and a G in place of the previous F#. Reversing strategies, the two-bar 7/8-plus-4/4 riff shown in Ex. 5 is derived from Examples 2b and 2d, and recalls another classic Beck tune. This time we literally play every sixteenth-note in bar 1, followed by the first eight sixteenths in bar 2. The C#-minor-based figure’s numerous hammer-ons allow it to roll right off your fingers. (Tip: Don’t forget to palm mute.)

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Ex. 6 features the return of the lush, open Em9 voicing that has appeared in several previous Rhythm Workshops. It’s used here to demonstrate Ex. 3a’s 3x5 subdivisions, but you are highly encouraged to substitute other chords and picking patterns. Ex. 7 inevitably delves into Mahavishnu territory with the application of a bluesy, A pentatonic-minor-based ostinato to Ex. 3b’s 5x3 subdivision, which has been embellished in the fifth grouping with a zippy sixteenth-note lick. Tear it up and experiment by applying different notes and rhythms to this and each previous subdivision, as well as transitioning from one to another.

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