The music, Maurice Wright's "Solos," has a movement titled "Ghost Songs," and the scene at its performance Saturday night at the Hirshhorn Museum was in fact ghostly. Flutist Sara Stern stood alone on a packed stage. Behind her was a harp, tuned and ready, with no harpist in sight. Flanking her on all sides were empty chairs with empty music stands.

Stern had three flutes of varying sizes, one for each of the work's three movements, but the sounds filling the auditorium were not merely hers. There was an invisible organ -- deep, rich and haunting in tone; a room full of metallic percussion, pinging and clattering from all sides; there was something that made a noise like wind blowing through a hole in a window, and something else that sounded like the world's biggest slide-whistle. There were squeaks, grunts and groans that could not be identified with any instrument.

All these sounds, interlocking ingeniously with her delicate threads of solo melody, were produced from a standard magnetic tape, encoded partly from a synthesizer and partly from natural sounds. As striking as the sound was the lyricism in Wright's music -- perhaps a part of the avant-garde's current effort to reach out and touch audiences. At any rate, it was strangely beautiful, with the accent on the second word.

"Solos" was one quarter of a fascinating program with which the 20th Century Consort opened its fifth season, affirming once again its unique and essential role in the musical life of this city. Stern also had the spotlight in another splendid moment: the exquisite slow movement ("Nocturne") of George Perle's atonal but accessible Sonata a Quattro. Perhaps the most enjoyable work of all, in composition and performance, was the Sonata for Clarinet and Piano, composed by Leonard Bernstein when he was 21 and interpreted magnificently by Loren Kitt and Lambert Orkis.

The program concluded with "La Vita Nuova," settings of five poems from the Italian Renaissance by British composer Nicholas Maw. In this work, the chamber-orchestra accompaniment often seemed more interesting than the vocal music (particularly in the fine writing for solo winds). This is no reflection on soprano Lucy Shelton, who sang beautifully, but on the composer, whose imagination (at least in this work) seems primarily instrumental.