The opportunity to hear a string quartet in the Barns of Wolf Trap is one of the things that make Washington a special place for lovers of chamber music. Not that we suffer a shortage of string quartets in such prime locations as the Library of Congress, the University of Maryland and the Corcoran Gallery, but there are few concert halls anywhere in the world that have the Barns' ambiance and acoustics.

Above all, the barns' wood, seasoned for two centuries, gives a special glow to the sound -- like the tone of violins of similar vintage -- without any loss of clarity.

The effect has been enhanced still further by the addition of removable wooden screens on the stage that help to focus and project the sound.

On Saturday night, all these elements were placed at the service of the Audubon Quartet, one of America's leading younger groups in this form of music making, with results that were a sheer delight.

The program was devoted more or less to first quartets in nicely balanced and contrasting styles. It opened with Beethoven's brilliant, dramatic Quartet in F, Op. 18, No.1 -- actually written second but published as No. 1.

It continued with Barto'k's First Quartet, Op. 7 -- actually his second, but he suppressed the first. And it ended with Mendelssohn's well-crafted, gently sentimental Quartet in E minor -- his first, though it was published as Op. 44, No. 2.

All were well performed, but the Barto'k was the highlight of the evening. Somewhat overshadowed by his later quartets, in which brilliant new musical paths were spectacularly opened, it is worth more attention than it usually receives, and the Audubon did it full justice.

Tightly written with considerable emotional energy, Op. 7 shows Barto'k emerging from the Germanic tradition in which he was trained and embracing his Hungarian heritage in the folk motifs that appear in the last movement.

Many styles jostle one another in this music; traditional forms, such as canon, are used in creative new ways and emotionally the modern sensitivity can be heard emerging out of romanticism. These elements were effectively presented in a vigorous performance that combined impressive technique with structural clarity and deep emotional commitment.