His back is arched like a wide bridge and his Fender Jaguar hangs low, maybe a foot above the stage. When Ira Kaplan, singer and guitarist for Yo La Tengo [ tickets ], pours noisy torrents of feedback onto some stage somewhere, this is his shape of choice.

Tuesday night (6/1), that stage was inside the Henry Fonda Music Box Theater in Hollywood. And, yes, Kaplan was hunched over. A lot.

Together with drummer/singer/wife Georgia Hubley and bassist James McNew, Kaplan seared through more than two hours of rock and roll, selecting tunes from a career that, believe it or not, is coming up on 20 years.

Although opener "Today is the Day," off last year's "Summer Sun," was choppy, with Hubley's barely intelligible vocals taking the hard way through the mix, the following song, "Autumn Sweater," was better. Here, Kaplan was at the keys, singing. Wearing blue jeans, a red T-shirt and orange Chuck Taylors, the bushy-haired artist droned long chords on an organ while Hubley and McNew pulsed out a cool, ethereal break beat. Next, as it lurched into "Let's Burn Tony Orlando's House Down," the band was set to a backdrop of lava lamp-inspired sunrays.

Despite the wobbly start, Yo La Tengo gave its fans much to scream about. Their performance was as diverse as their catalog, a spectrum of noise, calm and funk. Through it all, Kaplan and Co. entertained--the perfect East Side hosts to this West Side crowd.

By 10:45, Kaplan had elected an audience captain, and later hopped into the crowd to interview some fans, after deciding that "the captain thing wasn't working." Some sample questions: "Where do you go to school?" "What do you hope to do after you graduate?"

Yet it was the music that made the night. On "Nowhere Near," Hubley, her voice now even and warm, sang, "All I know is when you smile/I believe in everything." In a moment, her song's slow, meditative rhythm would be juxtaposed by Kaplan's frenetic guitar scribbling, sounding like a cat on some crazy cocktail.

Inspired, the band shuffled some Motown-style antics onto "Nothing but You and Me." As Kaplan sang to a pre-programmed backing track, McNew and Hubley became an old Motown group, synchronizing moves, which included some hand jive and a spin and the requisite, "Shoo-wop, shoo-wop."

With the next song, YLT was back at the feedback fortress. "Cherry Chapstick" abused the senses with whacked-out soloing and crashing cymbals. Then came the Prince-worthy funk of "Close Your Eyes." Kaplan returned to the keyboard, twinkling melodic lines with his left hand while his right hand held the mic close to his lips.

Surely, there aren't too many bands that can teeter on the borderline of performance art and rock-concert kitsch in this way. The final 20 minutes featured the Kinks' "There Is No Life Without Love," with Hubley and Kaplan sharing beautiful harmonies; Black Flag's "Nervous Breakdown," with McNew growling out his vocals; plus another pretty ballad and another noisy jam.

This kind of diversity is certainly great on the ears. And, if Kaplan's flexibility is any hint, it must do wonders for the back, too.