Influenced by a range of artists that includes the aforementioned Williams as well as Willie Nelson, Metallica, and Deep Purple, SLR brings all of these unrelated influences together in a hyperactive bluegrass context under Rundstrom's direction. On In the Mud, SLR's sophomore release, the original trio was augmented with the mandolin of Wayne Gottstine, who also added guitar and vocals, as well as another layer of tradition. SLR pins its bluegrass-edged songs to the wall with a furious sonic delivery that owes its existence to the literal punk rock of the '70s as well as the punkish country attitude that transformed music in the '50s. Call it "speedgrass," call it "hellbilly," call it "heavy flannel" -- whatever you call it, you'll generally have to shout to be heard over it. Split Lip Rayfield occasionally throws in a handful of traditional-sounding bluegrass songs, but Rundstrom and Mardis prefer to speed-pick their way through their decidedly nontraditional material, leaving purists and nonbelievers trying to figure out how to scratch their heads and plug their ears at the same time.