“Me and my different drummer/He play the timpanis,” Lupe Fiasco raps on his third disc. Dude’s not kidding. Few rappers this side of his fellow Chicagoan Kanye West bring left-field bombast like the man born Wasalu Muhammad Jaco. His last disc, 2007’s The Cool, was a 70-minute quasi-concept album about the search for sociopolitical realness in a fallen gangsta world that still managed to give him a hit (the anti-stardom “Superstar”). The long-awaited follow-up, Lasers, is shorter, brighter and — most admirably — more optimistic. It places Lupe in a tradition that runs from Marley to M.I.A.: the soul rebel who refuses to believe righteous struggle has to be a grind. “Just listening to ‘Pac ain’t gonna make it stop,” he raps. “The Show Goes On” cleverly reworks the chorus from Modest Mouse’s “Float On” for an inspirational missive to global ghetto kids, and John Legend adds R&B honey to the otherwise somber “Never Forget You.” Lupe’s beats run from Nineties buoyancy to driving rap rock, but his most exciting tracks are operatic brawlers that give his athletic, whiplash flow and rich imagination room to move. “All Black Everything” isn’t just utopian, it’s hilarious too, visualizing a world where MLK is still with us, Bill O’Reilly reads from the Koran, “Somalia’s a great place to relax in. . . . [And] the Rat Pack was a cool group of black men.” A guy can dream.