There were audience members seated on the stage last night in the Kennedy Center Concert Hall--an ominous sign. This kind of overflow crowd seems to deaden the acoustics a bit, and it usually flocks to honor exaggerated reputations like Cliburn and Pavarotti. But last night's concert was all right if not dazzling. A program of Beethoven trios was being played by Vladimir Ashkenazy, piano; Itzhak Perlman, violin, and Lynn Harrell, cello--three of the finest musicians today, all adept in chamber music techniques and nuances, and properly deferential both to one another and to the music.

The performance was nearly flawless, though a bit cool in the opening little allegretto in B-flat. The players' rapport warmed perceptibly during the Trio No. 5 in E-flat and reached a fine peak in the evening's masterpiece, the "Archduke" trio. The keynote was balance and control, rather than the special excitement that comes when risks are being perceptibly taken.

What was missing--a sense of intimacy and spontaneous enjoyment--may be attributed partly to the size of the hall (which is at the upper limit of practicality for chamber music) and even more to the audience, which was really too large for the hall.

Perhaps the problem is the star mystique itself, a malady of epidemic dimensions in our time. It is now reaching chamber music and threatens to disrupt its traditional spirit, which is one of equality among the players, a fellow feeling with the audience and mutual exploration of the music.

These performers still do honor to that spirit, in their playing and their stage demeanor, but there are some conditions in which chamber music becomes impossible. Their extraordinary skill and the public's perfectly justified reaction to that skill may be pushing them close to such conditions. Are they really a chamber ensemble like the Beaux Arts Trio, which was playing elsewhere in town last night, or are they three jet-set stars whose orbits occasionally intersect?

Chamber music was born in and for private homes, grew up in concert halls but has now come back to many homes largely through television. The growth of the audience is obviously good for chamber music in the long run--though that goodness should reach its mark in the work of many small groups in small halls, not necessarily a few star ensembles in big halls. Chamber music will undoubtedly emerge stronger from its present crisis of growth, but meanwhile we seem destined to live through what the old Chinese curse calls "interesting times." A group like the Ashkenazy-Perlman-Harrell trio helps to heighten that interest.