Knoxville-based songwriter Cruz Contreras is known primarily for his work with bluegrass outfit Robinella and the CCstringband, his long-running project with ex-wife Robin Ella. Now, Contreras flexes his Americana muscles with the folky, countrified group The Black Lillies, whose sound draws from roots-based music but displays a contemporary awareness. The rare indie act to infiltrate the mainstream country scene, the Lillies have played the Opry and enjoyed moderate chart success with this year's Runaway Freeway Blues. Nashville's The Howlin' Brothers is a "three-piece string band"—guitar, banjo, upright bass—that sticks more vehemently to a traditional sound, playing lived-in and instantly lovable tunes flecked with dirt and sunshine. The band's debut album, Howl, was released earlier this year to much acclaim.