Two years ago, in the Library of Congress, cellist Joel Krosnick of the Juilliard Quartet gave the world premiere of a Morton Subotnick composition called "Axolotl." He was aided and sometimes overwhelmed by a computer that took his cello's sounds, modified them according to the composer's prearranged instructions and pumped out electronic sounds through loudspeakers. It was a strange and wonderful experience, and it still is on the Nonesuch recording, even without a visual dimension to show the cellist alone but undaunted by all the sound whizzing around him.

Last night, on the same stage, Krosnick encountered Subotnick and his computer again in the world premiere of "The Fluttering of Wings." This time, Krosnick had with him his three Juilliard colleagues, their instruments wired with contact mikes like a very refined rock group. Subotnick's computer is now more sophisticated, its manipulations more subtle; it is sometimes hard to tell which sounds are coming directly from the quartet and which are the product of the little black box sitting on the front of the stage. It is still strange and wonderful, and with a whole quartet feeding it, the computer has a broader range of sounds to manipulate, but the gain in musical texture is somewhat offset without the visual impact of a solitary player confronting the machine.

This kind of music, which needs to be heard more than once, will be performed again tonight and broadcast live on WETA-FM (90.9). Also on the program is Schubert's "Death and the Maiden" Quartet, which received an impassioned performance last night but one not quite up to the Juilliard's best previous standards for precision. In Mozart's great Duo in G, violinist Robert Mann and violist Samuel Rhodes were eloquent and wonderfully coordinated.