Gregory Porter possesses a cool, comforting croon that's elevated the California native to the forefront of contemporary American jazz. But while he's the sort of singer who'd sound right at home serenading last-call drinkers in some smoke-filled, after-hours speakeasy, Porter's no purist: His 2013 Blue Note debut, Liquid Spirit, was steeped in sweaty soul and foot-stomping funk, and he lent his powerful pipes to British house-pop masters Disclosure's “Holding On."