One of the genuinely formidable programs of the concert year was performed last night at the Library of Congress by mezzo-soprano Elaine Bonazzi and the Da Capo Chamber Players under Frederik Prausnitz.

The main work was that epochal creation of 20th-century vocal music, Arnold Schoenberg's song cycle (or, as he called it, "melodrama"), "Pierrot Lunaire," in a vivid new translation from the German by Andrew Porter.

"Pierrot" is apt to dominate any program, with its considerable scale, its intricacy and its nightmarish imagery -- not to say also for Schoenberg's famous vocal invention, sprechstimme, the intense half-speech, half-singing that has radically changed the vocabulary of song in this century.

If one can think, though, of another 20th-century set of songs that comes close to the rigor and starkness of the Schoenberg, a strong candidate would be the other set on last night's program, Ravel's "Chansons Made'casses" for voice, flute, cello and piano. These three songs of Madagascar are shattering in their impact, especially in the virulently anticolonial central one, "Aoua! Aoua!," with its final exortation, "Mistrust the whites, dwellers of the shore."

Bonazzi's singing in the Ravel was, as it should have been, more hard-edged than sumptuous. The end of "Aoua! Aoua!" was devastating in its nonvibrato hush, as was the unaccompanied end of "Il est doux."

Porter's new translation of "Pierrot" goes a long way toward capturing the jaundiced hedonism of the 21 poems in their German original. Some of these images are marvelous, as in "The Crosses": "In their bodies swords have feasted, glorying in their robes of scarlet!"

The singer's role in "Pierrot" is awesomely difficult, and Bonazzi was superb. The chamber ensemble was also fine, with especially outstanding playing of those difficult cello solos by Andre' Emelianoff.

In an inspired afterthought, Prausnitz balanced this program of 20th-century musical austerity with a Schoenberg chamber orchestration of that ultimate 19th-century wonder, Johann Strauss Jr.'s "Emperor Waltz," fetchingly played.