PREVIEW K’naan opens his sophomore album, Troubadour (A&M/Octone), with a true urban legend: it’s tougher in Africa than anywhere else. "Here the city code is lock and load /Any minute, it’s rock ‘n’ roll," he raps in an ode to his native "Somalia."

Having established his ghetto bona fides, the Canadian immigrant embarks on a conscious party, playing with U.S. hard rock ("If Rap Gets Jealous" with Metallica guitarist Kirk Hammett), radio-friendly pop ("Bang Bang" with Maroon 5 vocalist Adam Levine), and Jamaican ragga ("I Come Prepared" with Damien Marley). Effortlessly sliding from twisty rap lyrics to midrange vocal tones, K’naan’s resolute optimism comes from having survived incredible poverty and hardship. "I’ll probably get a Grammy without a grammar education," he adds on "Somalia," "so fuck you schooling, fuck you immigration!"

K’naan appears with Stephen and Julian Marley and Lee "Scratch" Perry at the Ragga Muffins Festival this week.

RAGGA MUFFINS FESTIVAL With K’naan, Stephen Marley, Lee "Scratch" Perry, Julian Marley, and Rootz Underground. Fri/20, 7 p.m., $37.50. Fox Theater, 1807 Telegraph, Oakl. (415) 421-TIXS, www.thefoxoakland.com