Sweet, seductive and subtle, Philly Soul was the uptown R&B sound of the 1970s. Kicked off at the end of the hippie era, the musical style was defined more by the Philly-based production/songwriting duo Gamble & Huff than by city-specific artists. Gamble & Huff combined the best parts of early Motown and classic R&B vocal groups with Curtis Mayfield's Psychedelic Soul and post-What's Going On Marvin Gaye, then filled it out with their own lush studio sound. Philly Soul instrumentation brims over with funky electric bass lines, solid percussion tracks (from congas to cowbells to non-stop high-hat action), stabbing horn charts and sweeping string sections. The music works on the dance floor or in the bedroom, but many songs/albums of the genre also have an overt social or political edge. The O'Jays were the single greatest Philly Soul act, working personal, political and emotional themes into a string of great albums, including 1972's classic Back Stabbers (which contains the joyous Disco blueprint "Love Train"). Harold Melvin & the Blue Notes, featuring lead vocals by Teddy Pendergrass, were another amazing Philly Soul vocal outfit who had plenty of hits throughout the '70s. Gamble & Huff's magic also revived the careers of two of Chicago's greatest soul singers, the urbane Jerry Butler and the more gritty Lou Rawls, while Philly native (and old G&H associate) Daryl Hall took the style in a different direction with Hall & Oates. The Philly Soul sound was so popular that many other soul and pop artists started copying it, causing the sound to split rapidly into Disco, Quiet Storm and Smooth Jazz. Boz Scaggs' "Dirty Lowdown" and David Bowie's "Young Americans" exude the upscale vibe of Philly Soul, while today's Neo-Soul acts are spreading the genre's penthouse and pavement gospel to new generations.