When a violinist has as much performance and teaching mileage as Jaime Laredo, any 70th-birthday concert is bound to have meetings of remarkable musicians. Lots of them. The big piece at "Jaime Laredo and Friends" on Sunday at the Curtis Institute was the Mendelssohn


. Half the eight musicians were people I'd go to hear as individuals.

Though often played by two string quartets in tandem, Laredo's ad hoc group worked just fine, perhaps because the musicians have common lineage - Laredo as a longtime colleague or teacher. Also, the piece is organized along such clear classical lines that musicians need not hide their lights under a bushel to keep from getting in the way. Laredo was obviously the leader, but violinists Soovin Kim and Pamela Frank, violist Hsin-Yun Huang and cellist Sharon Robinson all made their presences felt, though not obtrusively.

Though the piece contains a fair amount of intricacy, any number of moments almost had a mushroom-cloud effect, in which the collective energy of the group burgeoned into gestures whose magnitude was such that the eight musicians sounded more like 40.

Though one tends to remember the Octet's youthful energy above all else, the maturity of the performers gave the piece's excursions into minor keys a weight that eclipsed sunnier passages. Only in the third movement (which shows Mendelssohn in A Midsummer Night's Dream mode) had the kind of playing that reminded you of the ensemble's ad hoc status. Above all, the performance had a grand sense of occasion - as one could see from the long-absent Frank's outward exuberance. Think of how exuberant audiences would be if Frank graduated from second violinist to first.

The rest of the program showed Laredo in good form. Though there's no denying that he's a 70-year-old violinist, he's one who has been practicing. Even so, Bach's Concerto for Two Violins showed how baroque performance has evolved. Laredo epitomizes the 1970s era of the Marlboro Festival, where Promethian truth took precedence over grace and style. In Bach, that translated into a muscular tone that didn't accommodate the details more easily managed by violinist Bella Hristova and the Curtis Chamber Ensemble.

His finest moments were in Suite in G minor by Moritz Moszkowski (1854-1925), a name known mostly today for encore piano works. This consistently strong piece for two violins and piano (Laredo was joined by violinist Jennifer Koh and pianist Benjamin Hochman) has a meltingly beautiful slow movement whose lyrical tenderness seamlessly slips into an unresolved, Semitically tinged melancholy like nothing this side of Gustav Mahler. Koh tempered her usual glow-in-the-dark tendencies, yielding stylish playing that framed Laredo in ways that reminded you how tunes are only as great as their surroundings.