Great unknown bands abound in this town. The trick is finding them before they’re done being great or unknown or both. Take Sam Champion, whom I heard about from a blogger friend. On my iPod, their guitar-driven indie rock, with shaggy Pavement-like vocals, sounded pleasant and catchy. But onstage, they took things a step further, delivering a feedback-drenched wall of sound that was full of warmth and texture. “We just want to be sure the crowd’s having fun,” says singer Noah Chernin. “Rock music doesn’t have to be such a serious thing. Led Zeppelin sang about the Hobbit, you know?” Sam Champion could break out any minute—as could Matt & Kim, whom you’ve likely seen only if you frequent DIY one-offs held in dingy industrial parks. The punkish Williamsburg duo, who drew a following with their exuberant live shows, may or may not be the next White Stripes, to whom they’re often compared, but we wouldn’t put it past them. Finally, when Takka Takka scored an opening slot with former band-of-the-second Clap Your Hands Say Yeah, rock cognoscenti were alerted to their laid-back organ pop. Together for less than a month, they mesmerized fans at SummerStage, then played to packed shows at the CMJ festival. “Our first show was at Tommy’s Tavern in Greenpoint, the absolute worst place to play,” says singer Gabe Levine. “And we went from there to Bowery Ballroom in the course of a year. It’s been awesome.”