Schoenberg and Webern were the old-timers on the 20th Century Consort's program at the Hirshhorn Museum last night. They shared the bill with music by Schwantner, Wright and Crumb. Together, these five provided a fascinating insight into the different and intensely personal modes of discourse affected by the composers of this century.

Schwantner speaks colorfully. His language is full or ornaments and embellishments. His ideas are rolled about and restated -- and played with. He expressed himself intellectually.

In his "Elixir (Consortium VIII)," for flute, clarinet, viola cello and piano, several varieties of flutes and clarinets are played and the instrumentalists also double on finger-rubbed wine glasses and on bells. The flute is a soloist in this varied ensemble and the resulting interplay of melody and shifting sounds is marvelous.

Webern speaks elegantly, like a poet who wastes no words. His early Four Pieces for violin and piano, played with the intensity and concentration they demand, were tiny gems, balanced, complete and completely satisfying.

Maurice Wright speaks broadly, with double entendres, winks and guffaws. "Basilio's Lament," a theater piece, he program note said, is a rather nice work for soprano flute and piano with an obscure and occasionally humorous text. The note described all sorts of events that never seemed to happen, and a drama that never seemed to occur, but the music stood well without them.

Crumb speaks delicately.He always seems to be listening to himself and, like an actor, loves to hear himself talk. This performance of the Four Nocturns for violin and piano, with its puffs of sound and pregnant silences, like the music, seemed to be turned inward.

And finally, Schoenberg speaks like an orator, floridly and grandly, sounding, in this company, expansive and eloquent. His Chamber Symphony, written while he was still committed to romantic expressiveness, was rescored for flute, clarinet, violin, cello and piano, by Webern, and it was this version that the Consort played so splendidly last night.