This is the quality that changed most clearly once drill had become the sound of rap in London by the mid-2010s. In the hands of young Black British producers smitten by Chicago drill but raised on a diet of grime, dubstep, and other dance music, drill’s open space offered room for other rhythms to hop aboard. Appearing within a year of Chicago drill’s explosion, early UK drill tracks by Stickz or GR1ZZY & M Dargg emulated Chicago’s, save for the accents. Yet in just a couple of years, the beat shifted, inflected by the UK’s distinctive Afro-diasporic heritage. On many tracks, like 2014’s “No Rules,” by Section Boyz, the snare on the fourth beat recedes as other percussive filigree fills in. By 2016, the same beat was replaced by bubbling soca-style snares traveling twice as fast, as in 67’s “Lets Lurk.”
London producers sutured early drill’s half-step stomp to grime music’s angular, up-tempo grooves and timeless Afro-Caribbean polyrhythms. For timbres and arrangements, they likewise drew from a local palette: sinewy bass lines surreally sliding from one note to the next, cherished percussion bits sampled from such iconic grime instrumentals as Wiley’s “Ice Rink,” and snarling synth smears recalling dubstep’s half-time wobble With this infusion of energy and style, something subtle but crucial happened to drill’s formerly plodding beat: It began to float. While the first snare of the backbeat (on the second beat) remained prominent, a clear nod to Chicago and Atlanta, the second frequently failed to appear at all, or struck a beat later than expected. The effect was as if each bar contained a half-measure of Chicago “half-time” (at, say, 70 bpm), followed by a full measure of London “double-time” (140 bpm): ONE-and-TWO -and-1-2-3-4. In contrast to the typical trap/Chicago drill beat, the hi-hats have moved from on-beat and triplet subdivisions to a steady 3+3+2 polyrhythm, that mainstay of Afro-diasporic music from dancehall to salsa — what some would call tresillo, or what reggaeton devotees know as dembow.