It doesn’t get simpler than Classic: one MC, one producer, 10 songs, no guests. It’s been ten years since her debut, but Rah Digga brings the goods on her sophomore album. Classic is a tight-knit collaboration with Virginia producer Nottz, whose beats are hard and organic. His tracks are at once majestic and gritty — he spins together threads of school band orchestras, ‘70s blaxploitation funk, and the live hip-hop of the Roots. “Viral” and “Back It Up” are vertiginous tapestries of electronic sound, yet the rhythm and focus of Rah’s flow always keeps the songs grounded. “Who Gonna Check Me Boo” and “Straight Spittin’ IV” are monstrous sonic concoctions that rear up like typhoons. On the other hand, “You Got It” could be a rap song from a Bronx playground, circa 1979 — Nottz cuts up Bobby Byrd’s “I Know You Got Soul” as Rah lets loose on top of it. The drums are kicking, the bass popping — this is an album that deserves to be played at top volume. Classic proves it’s possible to embrace old-school values without turning music retrograde.