Thom Bell’s biggest coup as a producer, songwriter, and arranger was to give the already-sumptuous vocals of the Delfonics the most stunning backdrop any R&B harmonizers would ever need. Post-psychedelic touches (like the sitars in ornate breakup-to-make-up symphony “Didn’t I (Blow Your Mind This Time)”) mingle with Bell’s ear for turning airy strings-and-horns smoothness to make for a particularly intense sort of beauty. Raw soul partisans called it “easy listening,” but nowadays it’s only easy to be floored by the sheer craft of it.