With ups and downs, Alfred Nash Patterson and his ambitious Polyphonic Choir of Christ Church have been presenting rarely sung sacred music. Such a group is much needed in a community which spends most of its efforts on Bach's B-Minor Mass and Beethoven's Missa Solemnis. They were particularly welcomed Monday night when they gave Mozart's Great Mass in C Minor in its first Boston performance in Trinity Church. The crow which filled every seat and stood in every open space made this pretty clear.

More to the point, this was definitely one of the group's ups, and they performed the Mass with such success that its 160-odd years of neglect seem an unforgivable oversight. The only uncooperative figure was Trinity Church itself, which turned out to be an acoustical flop. It has no capacity for distributing sound throughout its Romanesque caverns, and if you were sitting as I was with the basses and tenors turned away from you, you scarcely heard them at all.

This makes the job of criticism particularly difficult, for, although the training and ensemble were clearly there, the sopranos were the only ones who provided any definition to the choruses. This was less true in the fugues which started in the basses. As soon as all four sections had joined in, however, only the top voice came through.

The Mass was written for available talent at Salzburg in 1782. In that case the abilities must have been reversed, for Monday night Paul Tibbetts did the best bit of solo work with the one short phrase that makes up the bass part. No one could have any criticism, however, of Eleanor Davis' "Laudamusic," which was altogether competent. The soprano, Phyllis Curtin, had the most difficult role of all, particularly in the jumps of the "Et incarnatus est." Though she had many exquisite tones, she showed a slight unwillingness to land decisively on a note and sustain it. Tenor Summer Crockett was inaudible at times during his soles and his voles unpleasantly constrained.

Great praise must' be given to the orchestra, which supplied the best accompaniment I have heard in a Cambridge group. But the laurels really belong to Mr. Patterson, the conductor. At no time was there the slightest doubt that he was in complete control and knew just what he was doing. He has a sense of contrast and dramatic effect which he has trained his musicians to execute. The mighty invocation, "Jesu Christe," followed by a bursting "Cum Saneto Spiritu" was as impressive as any singing around. Though the memory of the "Dona Nobis Pacem" was destroyed by a recessional hymn, it was, while it lasted, no less than magnificent.