WHEN OUT-OF-TOWNERS think of Atlanta, they might picture our downtown skyline, The Varsity drive-in, maybe the Braves’ Turner Field. But dig a little deeper and you’ll find a city with distinct neighborhoods that reach far beyond the well-known central destinations. A second look shows us that Atlanta has made itself a music hub — after all, this is the home of André 3000 and Big Boi of Outkast, T.I., Speech of Arrested Development, Killer Mike, HeaveN Beatbox, and CLAVVS.