One of hip-hop’s true enigmatic figures, foundational DJ Afrika Bambaataa now plies his turntable trade on the rave circuit, releases obscure electro records and espouses theories about the earth being hollow. Two decades ago, though, Bambaataa was the most propulsive force in hip-hop, and this collection ably captures his dance-floor magnetism, from “Jazzy Sensation,” where guest vocalists the Jazzy 5 salivate over the name of James Brown, to “Unity Part 1 (The Third Coming),” where the hardest-screaming man in soul business himself shows up at the party, shouting ecstatically, “Punk rock! New Wave! Peace! Harmony!” But “Unity” clocks in at a mere three and a half minutes; Bambaataa’s brilliance was his ability to let the beat go on, bleeding into the infinite. Epic productions like “Zulu Nation Throwdown,” “Looking for the Perfect Beat” and “Renegades of Funk” — all featuring the rap naif of the Soul Sonic Force — combine funky drums, stinging clap slaps and vocoded chants into beats that truly don’t stop.