The sequencer on the 808, a row of 16 color-coded buttons, offered artists ... era of hip-hop. But the 808’s initial heyday was short-lived and beset with naysaying: The machine was expensive.

In “Straight Loops, Light & Soul,” a project evoking Roy DeCarava’s Harlem jazz pictures and the music of J Dilla, Williams captures the underground beat-maker scene of Queens.