Yo La Tengo, Bush Hall, London <!-- none onestar twostar threestar fourstar fivestar -->

"People always laugh when we say that," muses a mock-bewildered Ira Kaplan, Yo La Tengo's singer-guitarist, after he announces the title of his band's new album tonight. That title is I Am Not Afraid of You and I Will Beat Your Ass, and the incongruity is winning. Far from ass-beating, virtuosity and a passion for the many forms of pop, allied with wit, warmth and plaintive charm, are the defining features of these US art-rock veterans.

You wouldn't want to tussle with them musically, mind. Kaplan and the drummer, Georgia Hubley, have been the core of the band since 1984; the bassist, James McNew, joined them in 1992. Since then, they have turned playing by intuition into a fine art, marrying a loose, seemingly freeform take on genres and, indeed, their roles within the band with the tension afforded by a simple three-piece set-up. Like the Velvet Underground, to whom they used to be often compared, they've consistently proven to be more than the sum of their parts.

That dynamism is highlighted in tonight's opening tracks. Culled from their new album, they turn on a dime sonically and lyrically, slipping from slabs of avant-psychedelic drone-rock to creamy, heartfelt pop and, on "Mr Tough", wry falsetto-funk.

Part of Yo La Tengo's art lies in making virtuosity and eclecticism look simple and seamless. Experimental as they are, they're never indulgent to the point of being alienating. Several songs played tonight are as striking for the nakedness of their lyrics and purity of their melodies as they are for their difference from other numbers in the set, a simplicity that is beautifully captured in the three band-members' limpid, non-fussy, ego-free vocal styles.

When they do let rip, though, it's a joy to behold. Tonight's opener, "The Story of Yo La Tengo", builds from a mantric drone into a sonic storm, driven by Kaplan's fearless playing. As Hubley and McNew keep a taut-but-fluid beat, Kaplan begins to convulse from his belly before tearing out a heroically skronky racket from his strangled and mangled guitar.

They're exhilarating, too, when they pack that kind of muscular musicianship into a tight rock song. The blues-punk stormer "Watch Out for Me Ronnie" sees Kaplan jack-knifing at his guitar from his shoulders, all the while unleashing a startling holler of a vocal.

At the risk of being over-literal, perhaps that album title is fitting, after all: modest and gentle as they seem, this long-lasting little band aren't to be underestimated.