Hoover From a classical point of view, Washington's summers are becoming a lot more active musically. Last night the Library of Congress put in its bid to spark the month of June with the opening of its first Summer Chamber Festival.

Under the artistic direction of Miles Hoffman, a violist with the National Symphony, the festival will bring together a dozen young artists from around the world in five programs over the next two weeks. The music will be a balanced selection from the chamber repertoire, ranging from such beloved staples as Schubert's "Trout" Quintet to works from this century.

At this first concert, composer Katherine Hoover came down from New York to hear the performance of her 1975 "Divertimento," which began the program. Written for flute, violin, viola and cello, it proved a most accessible work, crafted to reflect a pleasingly personal point of view. It received a sympathetic and well-integrated interpretation from flutist Pamina Blum, violinist Junko Ohtsu, violist Matthias Buchholz and cellist Evelyn Elsing.

For all the singing purity of her tone and sensitive partnership from pianist William Black, Ohtsu could not, however, redeem the slight fare of Erich Korngold's "Much Ado About Nothing." Sailing along a sentimental edge, the music, if half as long, would have been an amiable interlude.

Faure''s Piano Trio, Op. 120, also rambled on too long, getting bogged down in its own harmonies, despite some sensual playing from Elsing and Ohtsu. Pianist France de Guise's rather edgy and straight approach did not help. In the closing Brahms C Minor Piano Quartet, Elsing--filling in for ailing Belgian cellist France Springuel--joined pianist Andre' Laplante and violist Hoffman in an authoritative and frequently intense rendering. Violinist Mark Peskanov often seemed on another track, particularly in the Andante, which needed a bit more breathing room.

Tomorrow morning at 10 there is an open rehearsal for the Friday program, which features the "Trout" Quintet along with music by Debussy and the American composer Bruce Saylor.