The Carolina Chocolate Drops — banjo player Dom Flemons and fiddlers Rhiannon Giddens and Justin Robinson (they all sing and juggle guitar, Autoharp and percussion) — reignite a vintage outsider music: the early-20th-century jump and lamentation of black country string bands from North Carolina's Piedmont region. The Drops' marvelous new record has a proud and true title, Genuine Negro Jig (Nonesuch), and features exuberant treatments of antique party favors like "Cornbread and Butterbeans" and "Papa" Charlie Jackson's 1926 shuffle "Your Baby Ain't Sweet Like Mine." But the Drops, formed in 2005, are modern souls with a wider sense of roots. Giddens, who sang opera in college, delivers the revenge in Blu Cantrell's 2001 R&B hit "Hit 'Em Up Style" with steely, cutting force. And while the Drops play music that first came to America in slave ships, the Celtic air that haunts the plaintive fiddles in "Snowden's Jig (Genuine Negro Jig)" is a sly reminder that for most new arrivals here, life started at the bottom.