Americana’s jailbreak from sleepy town squares and the scratchier bands of the AM dial has been a welcome development in American music. And the renegade traditionalists of Mipso — Jacob Sharp on mandolin, Joseph Terrell on guitar, Libby Rodenbough on fiddle, and Wood Robinson on double bass — are doing their part to take three-part harmony and Appalachian influences into new territory. The three North Carolina songwriters have wandered off the path blazed by Earl Scruggs and Doc Watson to find a new clearing for their southern string band sound.