Reprinted from yesterday's late editions

Chamber music al fresco is a contradiction in terms, but if you are not a purist and are not averse to a classical string quartet partaking of some of the ambience of a summer evening, it is quite delightful.

The pieces that the Guarneri String Quartet chose for their program at Wolf Trap Sunday night made no concessions to the outdoors at all. Haydn's last quartet, the opus 77, no. 2, is a contemplative work with little of the joking and playfulness of his earlier music. In these surroundings it lost some of the details but gained a certain sense of universality.

Borodin's quartets are not exactly staples of the repertoire, but Borodin's catalogue, like that of Grieg, is a repository of an enormous number of those familiar passages you know so well but just can't place. Both the second and third movements of Borodin's quartet no. 2 are ubiquitous in soupy arrangements for string orchestra. But in their natural state, as played by the Guarneri, they were charming.

It was in the playing of the Mendelssohn D major quartet, opus 44, however, that the unusual strengths of the Guarneri were most in evidence a virtuoso alacrity tempered by sweetness. Darkness by then having quieted the birds and other creatures, the music could be savored in detail.