"ONLY amateurs should play music," said someone in the audience at Saturday's Bach Society concert. The kind of excitement about the music that John Adams elicits in the members of his orchestra carries composers' intentions to audiences and makes the Bach Society Orchestra a fine group.

A strong, rhythmic Schubert's Third Symphony opened Saturday evening's program; basses and celli played with striking clarity, and the string sound was alive and tuned. The last three movements were less compeling in rhythm than the first, and the winds were often out of tune, but these were minor obstacles to the emotional realization of the music, which was always there.

The Mozart Symphony No. 36 brought forth better intonation from the winds, and the strings had a pleasing, gentle attack. Like the Schubert, the Mozart was alive, and never dull. Nevertheless, something was missing or misplaced. It was as if the excitement had become confused with the music, so that the detachment by Mozart was absent. Rather than feeling invited to view a large movement from above, the listener was immersed in the music, running after phrase upon phrase. Perhaps sharper contrasts of dynamics or articulation would have made the Mozart as enjoyable as the Schubert.

Most interesting in ways was the performance of the Bach E major Violin Concerto by James Oliver Buswell IV. It was practically unconducted, and that created obstacles to the flow from composer to listener. Buswell's head and body gestures did not keep the orchestra together or effect good ritardandi, and the reduced orchestra sounded best in the parts of the slow movement that Buswell actually conducted. Here he created a clearer pulse, sensitive phrasing of the bass line, and even, mysteriously, better intonation.

DESPITE problems, technique was good enough so that the music was presumably moving along as Buswell intended, and his approach was ill-suited to Bach. Rhythm in Bach grows from phrasing, not phrasing from meter; the over-all shape results from the growth of phrases rather than from dynamics or metric energy. The performance struck me as metrical in its phrasing, and in places, the bass line was simply un-phrased.

In non-musical terms, the force of Bach is in relatively inner things. Feeling is not expressed, to be incorporated again by the listener, but remains inner throughout the conveying process. Thus Saturday evening's performance of the E major concerto achieved vigor but not inner focus.

The audience and performers on Saturday night were caught up in enjoyment of the music. The Bach Society may be developing as devoted a following in the community as John Adams has in the orchestra.