**Swamp Dogg, James Intveld, DJ Jonathan Toubin** “Not a lot of people talk about the true origins of bluegrass music,” says Swamp Dogg, “but it came from Black people. The banjo, the washtub, all that stuff started with African Americans. We were playing it before it even had a name.” Swamp Dogg’s remarkable new album, Blackgrass: From West Virginia to 125th St., is no history lesson, though. Produced by Ryan Olson (Bon Iver, Poliça) and recorded with an all-star band including Noam Pikelny, ...