THE MASS IN B MINOR started out as part of a job application. When J.S. Bach wanted the job of Court Composer for King August II, he submitted parts of the Kyrie and Gloria as testimony to his ability and devotion. He got the job.

Bach built his Mass on a monumental scale, too large to be performed at a church service. Instead, it has become a standard choral work and a great landmark of Western music. On Saturday, the Collegium Musicum under F. John Adams gave a performance of it that almost worked.

The Collegium displayed the polished technique that has become the hallmark of Adams's choruses. Their tone was solid and well-blended; their diction was a model of properly popped consonants. Yet the performance didn't really get off the ground until well into the second half. Like a sonnet reader who calls attention to each iamb, Adams tended to emphasize the repetitive Baroque rhythms at the expense of larger phrases. Part of this problem can be traced to the widespread malady of the pick-up orchestra. This was the usual random group of instrumentalists thrown together to accompany a university choral group and as usual, they plagued the performance with ragged entrances, shaky ensemble, and a sight-reader's insensitivity to the meaning of the music.

Yet there were moments of great beauty. From the Incarnatus section to the final choruses, the performance gathered power and assurance. The Confiteor section provided outstanding examples of subtle, directional phrasing. The male solos were similarly convincing. Tenor Frank Hoffmeister and Bass David Evitts showed clearly why they are two of the busiest free-lancers around. They both posess a rich and confident tone, accurate intonation and the kind of innate musicality that makes satisfying performances a matter of course.

Soprano Judith Frankfurt, a member of the Collegium, made a successful solo debut. Her controlled light tone and sure sense of pitch put her on a par with her professional colleagues.

Adams's approach to the Mass was reserved and understated. He didn't try to overpower us with a huge sound or high drama. But too often his understatement communicated itself as squareness or lack of daring.