Fans of contemporary country have long marched to the sound of Southern rock, now a major component of country music. Rock-informed guitars are the instruments of choice for many younger country acts, many of whom could easily get away with a concert encore of Lynyrd Skynyrd’s “Sweet Home Alabama” or the Allman Brothers’ “Ramblin’ Man,” so established are such songs in today’s country-fan consciousness. So, while it might make sense for Southern-rock pioneer and veteran Gregg Allman to cash in his chips at the country table, that’s not the route he takes on Low Country Blues, his first solo album in nearly 14 years. On a collection dominated by obscure blues chestnuts, Gregg pulls surprising grit and range from a voice hollowed out by hepatitis C and decades of hard rock ’n’ roll living. The album plays like a tribute to an earlier era, rich with period atmosphere, and Gregg, as always, delivers an authenticity few white singers could muster. This disc, though, may give die-hard country fans the blues.