A tireless studio engineer throughout reggae’s golden age, Osbourne “King Tubby” Ruddock reimagined the interplay between bass and drums with every dub he mixed. This set of unreleased early-‘80s tracks finds Tubby mixing cuts from Jah Thomas’ Midnight Rock label, adding mineshafts of echo and dizzying effects to “North Circular Dub,” and making the drum-machine staccatos of “Cross Bronx Dub” take on a life of their own.