The Philadelphia Trio

The Philadelphia Trio, with its first engagement at the Phillips Collection in more than three years, made a most favorable impression yesterday afternoon, leaving one to wonder why the group hasn't returned to this city sooner.

The group has been together for almost 15 years, and its special attention to detail and nuance quickly becomes an expected norm.

In the opening Piano Trio in E Minor, Hob. XV. 12 by Haydn, pianist Elizabeth Keller used a feathery, though authoritative touch to create a solid foundation for the strings, a tactic that carried over to the "Bergerettes" by Martinu and the "Archduke" by Beethoven. The episodic "Bergerettes" featured seamless legato play by violinist Barbara Sonies and cellist Deborah Reeder.

It was the "Archduke" that really gave the trio a chance to shine. The andante cantabile movement was songlike and then some.

Beethoven's intentions were flawlessly realized, as each instrument produced glorious sounds individually, and powerful statements as an ensemble. Alexander String Quartet

The Alexander String Quartet, together just five years, combines the spark of youth with a singleness of purpose usually reserved for more seasoned ensembles. Friday night at the Barns of Wolf Trap, the musicians' controlled exuberance was unflagging and consequently produced superlative accounts of Beethoven, Barto'kand Mendelssohn.

The real surprise was Barto'k's Third, whose icy string sonorities and visceral rhythms can still provoke, not to mention shock.

One expected the players to show a glint of propriety; instead, they used their bows with a vengeance.