It would be difficult to improve on the Belceas' "Hoffmeister." They are not an ordinary competition-circuit quartet. For one thing, they put much more thought and effort into articulation than they do into pouring out sound. It wouldn't be quite fair to say that leader Corina Belcea sets the tone; it's truer to say that she embodies it. Her alert, zesty, occasionally impetuous style is the style of her three comrades-in-arms. And everything they do, they seem to do with one mind, not in the Borg-Collective sense of some of the more obsessively rehearsed quartets, but just because they all want the same thing.

In the "Hoffmeister," that meant richness tempered with spirited articulation. I don't think I've ever seen that viola part handled as well as Belcea violist Kryzstof Chorzelski did. It was all so deft that it was almost self-effacing, and yet it was marvelous playing. There's a place early in the "Hoffmeister"'s slow movement where the viola alone sustains through a rest. Just a held note, but in this case a held note to bring tears to the eyes.

It was the same in the more familiar Mozart quartet ending the program, the "Dissonant" (K. 465). This group has the exceedingly rare knack of doing things in consort without seeming to choreograph them. There were dynamic effects in the "Dissonant" that in other hands would've sounded contrived or precious. They didn't Sunday.

As for Britten's Third Quartet, which came in between — there have been many local performances by visiting quartets, this being the perfect piece for any quartet wanting to show its dedication to contemporary music (quasi-contemporary, anyway — the piece is into its fourth decade) without actually alienating anyone. None matched this, always alert, always full of life and attentive to color. Cellist Antoine Lederlin (with the Belcea only four months, though you'd never guess it) played the final Passacaglia with a mixture of wit and soul hard to describe. And second violinist Laura Samuel almost literally let all hell loose in the second-movement Scherzo, which begins as mayhem, gets all mellow for a spell, then goes nuts again. And Belcea's own performance of the central "Solo" was exquisite, gently and persuasively backed by her vibrato-free colleagues.