Okay, maybe the term “folk” is a slight exaggeration. But Crystal Monee Hall’s 2010 debut album, River Train, had all the right signifiers: an acoustic guitar, several original love ballads, a bluesy cover of Pat Benatar’s “Heartbreaker.” Originally from Virginia, Hall honed her chops at Greensboro Baptist Church, then moved to New York and — through a fortuitous sequence of events — landed parts in several Broadway musicals, including Rent. Since moving to the Bay Area she’s devoted those supple contralto vocals to her own material and to the Jazz Mafia Symphony Orchestra. In the past year alone she performed at Stern Grove, Monterey Jazz Festival, and the Hollywood Bowl. Hall can certainly lift an entire fifty-piece ensemble, but we still recommend checking her out in a lounge format. This woman kills.