As references to R&B began to reenter the lexicon, Larry Levan delivered mix after mix that fed into the resurgent groove. Released on West End in early 1981, “Heartbeat” became a standout release. Tee Scott came as close as anyone to keeping pace with Levan. Continuing to mesh innovative production values with a rhythm and blues groove, Kevorkian completed his own flurry of releases. The new wave of releases carried dance music into terrain that was grittier and tougher than anything occupied by late disco. Sugar Hill held onto its vanguard position in rap when it released “The Adventures of...