BARRAGE of advertising notwithstanding, neither of the Bach Society's two soloists appeared last Saturday night. Both Cambridge-born basso Justino Diaz and pianist Tedd Joselson were absent from the Sanders stage; their loss and the identity of their replacements was announced in the inaudible mumble characteristic of concert-hall speeches.

Nevertheless it did emerge that David Evitts and Gregory Shatten were the vocal and piano soloists for an extremely conservative program of Bach and Handel. The choice of works, by conductor Robert Baker, were in line with the Bach Society's year-long emphasis on music from the Bach-Haydn-Mozart axis, rarely exploring material before or after.

The good sense of this policy was evident in the performance given Bach's Brandenburg Concerto No. 4. The ensemble size, ignoring questions of actual baroque performance practice, was well-suited to the dry acoustics of Sanders Theater. Even the continuo part was heard with soloists or full ensemble, a difficult achievement.

There are three solo parts in the Brandenburg, two for flutes and one for violin. Both flutists, Halley Schefler and Ann Hoffner, were in tune with each other and the orchestra. They played the andante with great delicacy. Their care and concentration were not duplicated by Lynn Chang, the violin soloist. Chang has an excellent reputation and has often carried the Bach Society violin section. While his playing in the first movement was controlled and understated, in the fugue he appeared hurried and ill at ease with the complex solo figurations. This was surprising since his technique far exceeds the music's demands.

A third excellent wind soloist, Stephen Hammer, played the oboe for Bach Cantata No. 56. His contribution was the most exciting aspect of the piece. His phrasing of the obbligato line in the second aria demonstrated a facility with the instrument coupled with great sensitivity to precise imitation. The basso for the cantata, David Evitts, had been recruited in extremely short order. He sounded tired, with several lapses of diction and little variation of timbre or volume. In general, he was a shadow of the big, confident singer he had been just one night before as soloist with the Collegium in the St. John Passion.

Evitts also sang a minor Handel Italian cantata. The accompaniment was only of continuo instruments: harpsichord and cello. In these intimate circumstances, Evitts sounded much better.

His performances were badly hurt by the neglect of the Bach Society management. Their priorities in printed program material for the audience are in need of revision. There was no translation of the German for the Bach; and no original text, translation, or even title published in the program for the Handel. It is far too much to ask of a performer that his audience listen in total ignorance of the words. This neglect is even more glaring in light of the orchestra's willingness to publish the original soloist's biography on an insert that could have been put to better use.

The Bach D Minor Concertowas given a solid performance with Gregory Shatten. There was an occasional disagreement in tempo between solo and conductor and some mechanical-sounding scale passages, but Shatten's playing covered a wide range of emotions. He maintained a beautiful soft volume in parts of the first movement and concluded it with a brilliant cadenza.

The credit for rescuing a concert abandoned by its soloists at the last moment belongs to Robert Baker. He kept the orchestra together through the difficulties inevitable in such a situation. His sense of ensemble balance, his greatest asset as a conductor, has been a tremendous gain to the Bach Society.