THE Bach Society Orchestra concert was the major disappointment of last week's musical offerings. Many heads could roll when a collective effort like this goes awry, but the conductor, John Adams is the one who must stand in the dock.

The program Adams chose for the group demanded a far higher level of musical competence than one can reasonably expect of any undergraduate organization--even one as fine as BSO. The works, Mozart's overture to "The abduction from the Seraglio", Beethoven's Symphony No. 2, the Adagio from Mahler's Symphony No. 5, and Debussy's "L'Apres Midi d'une Faune", would trip up even the most agile professionals.

But let this pass: set aside the slurred inner voices in the Mozart, the gaping holes in the Beethoven where one fully expects to hear second violins and violas, the cracking and blasting brass, the consistently out of tune winds. These are the agonized sounds (or silences) of musicians stretched beyond their capabilities.

There was an even more fundamental disparity between the orchestra and its program. The Bach Society simply does not have enough string players to cope with the grandness of Beethoven or the expansiveness of Debussy.

The winds were always successful in outblasting the strings and often completely obliterated the fiddlers who seemed in particular to be their mortal enemies. The leather-lunged trumpets vandalized the two outer movements of the Beethoven, while percussionists ran roughshod over the Mozart overture.

Any attempt Adams may have made to impose order was unsuccessful. The Debussy failed to take on any overall shape and, apart from Geoffrey Greenfield's competent flute solo, few distinct lines were extracted from the prevailing mire.

THE Mahler movement was the supreme irony of the evening. Rendered almost trivial by the surgery which removed it from the symphony, the Adagio was given a sympathetic performance despite the inevitable failure of the undermanned strings to produce the necessary breadth of sound.

A special citation for insubordination and vulgarity beyond the control of any conductor is in order. This to the tympanist who, juggling his sticks with the dexterity of a weightlifter, produced a sustained, and equally unwanted cannonade, the likes of which has not been heard since the retreat from Dunkirk.