There are choral works harder to sing than Bach's Mass in B minor, which the Paul Hill Chorale presented Saturday night and Sunday afternoon at the Kennedy Center. Beethoven's Missa Solemnis, for one, tests the strength and range of the human voice much more severely. But Bach's opus, relatively gentle to the singers, confronts the conductor with a jungle of perplexities and hard choices.

Not that the musicological answers are terribly hard to find, but once found they can be hard to accept. A diehard purist performance, for example, should probably have a chorus consisting of not more than two dozen men and boys - a far cry from the hundred-plus men and women (with women predominating in approximately a three-to-two ratio) who sang in these performances. Elsewhere, baroque purism is helpful to a large amateur chorus that wants to do Bach; it dictates that the orchestra should be small and the hard-pressed budget cries a ringing "Amen."

Hill's answer to these challenges was (as might be expected) an intelligent compromise between baroque purity and the modern (i.e., 19th-century) oratorio tradition; he assembled a small but good orchestra, and most of the time he had his large chorus sing with the lightness and transparency of a small one.

As a result, the orchestral texture (if not James Weaver's hardsichord) was audible except for a few a few exceptional climaxes, yet there was no feeling that the chorus was holding back - as it must have been. A few bits of choral virtuousity may have been more operatic then religious in effect, but they were nontheless stunning. All four solo singers were quite satisfactory and tenor Curtis Rayam was somewhat more than that.