The Juilliard may have miscalculated by starting off with the Opus 127 quartet at its all-Beethoven program at the Library of Congress last night. Just as athletic teams need to warm up before a game, musicians need some time to warm up to each other and to the acoustics, and that big E flat Major quartet offers neither time nor mercy. Its beauties lie in the subtle coordination of voices, in the intricate interrelationships that develop. There is little space for lyrical expression or time for sonorities to establish themselves.

Last night's performance held moments of magic--in the lovely balance of lines that emerged unforced in the opening of the second movement, and in the deliciously pointed beginning of the third--but overall, it never jelled. For one thing, first violinist Robert Mann was not in top form and had trouble throughout the evening with intonation and precision. For another, the ensemble's playing lacked intensity, usually the Juilliard's strong point.

The relative simplicity of the Opus 18 No. 2 quartet that followed brought back some of the style and flair that the Juilliard has spoiled us with for many years. It also underscored, startlingly, the distance Beethoven traveled in the 25 years that elapsed between the writing of these two works.

The quartet Opus 59 No. 2 ended the evening on an uneven note with nicely focused and coherent ensemble in the first two movements giving way to a certain amount of disorder in the last two.

Juilliard performances are usually not immaculate and usually it doesn't matter. Last night, it did.