Easily the hardest-working and one of the longest-running rhythm sections in the history of Jamaican music, Sly Dunbar and Robbie Shakespeare have provided the backbone for so many tracks in their 40-plus-year run that it's almost incalculable. In the course of that run, when not crafting what would become classic riddims or backing up pop stars, they were also involved in some of the earliest waves of dub, releasing dub sets like Raiders of the Lost Dub and Gamblers Choice under their own name as well as laying the foundation for countless dub mixes with their playing. Blackwood Dub, the first strictly dub, vocal-free offering from the duo in many years, revisits some of the tenets of dub they helped develop, sometimes leaning toward the nostalgic, but staying progressive overall. The cavernous production and eerie percussion touches on "Riding East" have a decidedly vintage sound, harking back to the Channel One days. "The Bomber" fits into this pre-'80s sound as well, with Lee Perry-esque weirdo electronic flourishes riding Sly's hypnotic Syndrum rhythms. Throughout Blackwood Dub there are new subtleties that acknowledge the infusion of dub into the digital world that's happened in the time between its roots in the '70s and the very different landscape of 2012. The watery electronic bubblings that underscore "Burru Saturday" and "Communication Breakdown" add life and a slightly modern feel to these masterful rhythms without edging toward dubstep or breaking the flow of the album with radically more electronic production. Likewise, the droning "Frenchman Code" leans ever so slightly away from the classic dub formula, taking on an almost mantric quality in its repetition. Dunbar's unwavering bassline coasts on tabla-informed drum patterns and stereo delayed bursts of Mikey "Mao" Chung's slinky guitar lines. The ten songs on Blackwood Dub represent less of a look backward or forward for Sly & Robbie as they do a continuation of a still growing tradition. It could be backing up Britney Spears or laying down a set of burning dub tracks such as these. At this point it's just another day at the office for the Rhythm Twins, in the most natural, organic, and exciting way possible.