Why do hip-hop producers gravitate toward jazz samples? For a mood, for sonic timbre, for a unique rhythmic component. Swing is a precursor to the boom-bap. "If you're a hip-hop producer that wants a lot of melodic stuff happening," pianist Robert Glasper says, "you're probably going to go to jazz first." Glasper has lived in an area of overlap between jazz and hip-hop for more than two decades —