As I was walking up to Avalon a week ago Tuesday to see the Roots for the first time in nearly five years, a group of college kids crossed the street in front of me sporting backwards hats and puffy vests. Surely they weren’t also headed to Avalon, right? Or am I so out of touch with frat culture that I wasn’t aware that the Roots have become the new Bob Marley? The Roots have long been a group tailor-made to cross over to a rock audience and to hip-hop dabblers who refuse to believe mainstream rap has anything to offer. And they’ve filled that role well. But as I watched a crowd that could easily have migrated to the nearest Dave Matthews concert nod along to the beats, it took an effort to remember that the Roots are a thoughtful, challenging band, and that they remain top-notch, high-energy hip-hop performers.

They lived up to that reputation at Avalon by marching in through the audience from the back, horns and all, with drummer ?uestlove on cowbell and rapper Black Thought poised to pounce on stage and launch into the title track from Game Theory (Geffen/Interscope), their latest. The performance was marred by too many mild instrumental solos and repetitive jams, and the absence of Malik B, whose dynamic interplay with Black Thought used to help break up what was otherwise a one-note delivery, is still a problem. They got around that by sticking to the best of their recent material, groove-heavy tracks such as “Star” and “Don’t Feel Right.” But when Black Thought, supported as usual by a full band complete with horn section, declared, “This is real hip-hop,” I couldn’t help thinking, “Well, no, technically it isn’t.” Hip-hop originated with turntables and microphones, not live backing bands. And when the group offered a tribute to J. Dilla, I couldn’t help wondering how many people in the crowd even knew who the late producer was: 25, 30 percent tops?