The conventional bluegrass categories of traditional and progressive are of little help in describing the music of the Nashville Bluegrass Band. Made up of top Nashville musicians who have devoted themselves to cultivating a unique group sound rather than displaying their individual talents, the band performs classic bluegrass numbers and contemporary songs from the likes of Gillian Welch and Kate Campbell with equal ease. They have been especially noted for their close harmony singing and, almost alone among bluegrass bands, for their investigation of the African-American roo...