Once asked how he felt about being sampled so prolifically in hip-hop, Delfonics co-founder and lead vocalist William Hart said he was grateful, and that he got it: The Delfonics helped make hip-hop a little cleaner. He meant it in the sense of profanity, but also in the sense of the songs' touch. Starting in the late '60s, the Philadelphia group pioneered a gentle, soft-focus sound with songs such as “La-La Means I Love You” and “Didn’t I (Blow Your Mind This Time).” Their music not only served as counterpoint to the grit of Otis Redding and Sly Stone, but helped foster an entirely new branch of soul, from the sophistication of quiet storm to the ethereality of alternative R&B: soul not as raw expression, but atmosphere and introspection.