Vivaldi's Concerto in C Major with solo oboes and clarinets isn't exactly "new" music, but it's the music with which the American Camerata for New Music chose to begin Sunday afternoon's program at the University of the District of Columbia's Fine Arts Auditorium.

Perhaps the ensemble, conducted by John Stevens, temporarily abandoned its usual 20th-century repertoire to honor a composer who was virtually rediscovered just decades ago.

At any rate, the Vivaldi was a well-chosen warm-up piece for Carl Ruggles' "Men and Mountains" (a "Rhapsodic Proclamation for Symphonic Ensemble"), Andras Szollosy's Concerto No. 3, composed in 1970, and Wagner's "Siegfried Idyll." Although the Wagner is nominally a 19th-century work, it was chosen for the composer's influence on 20th-century music and because the Camerata played the works at the close of its premiere concert 10 years ago.

Ruggles' 1924 work, though puzzling (can one "proclaim" a rhaposody?), was provocative for its solo French horn work and for its subtle solo string work. Although the ensemble's limited range of dynamics and small sound prevented it from doing justice to the Wagner, the Camerata fascinated the audience with the Szollosy. This prize-winning work calls for 16 string players to eke out fragments of melody from a peculiar amalgam of glissandi and pizzicati. The result was an enchanting siren wail from the grave, punctuated at the end by the ominous strokes of a chime.