EXCEPT UNDER the most felicitious circumstances, it nearly always happens that ensembles of the genre piano trio readily become a battle of bowed and percussive strings. To begin with, one rarely hears a well-established trio--compositions of this type are more frequently presented by three soloistic virtuosi who, for various reasons, agree to tolerate each other for an evening of 'chamber music.'

The pianist, inappropriately armed with an instrument designed to combat a full orchestra, obviously wins, unless he can be persuaded to restrain his superior forces; second place usually goes to the violinist, by virtue of the brilliance of his upper register. In third place is the cellist, ironically playing perhaps the most expressive of the three instruments. And the composer is fortunate, indeed, if he receives an accidental honorable mention somewhere in the midst of the bellicose uproar.

Monday evening's program at Burden Hall, the econd concert in the Harvard Summer School Series, consisted entirely of trios by Brahms--two for the standard combination (opp. 87 and 8), separated by the beautiful trio op. 114, in which the violin is replaced by a clarinet. The performances of the former works was atypical in one respect: violinist Roman Totenberg was the most prominent of the soloists. Cellist George Neikrug was, predictably, overpowered more often than not, while Leonard Shure unhappily assumed the role of piano accompanist, doing his best to stay out of the way through most of the evening.

Under the circumstances, it was perhaps the most charitable thing Shure could do. Burden Hall is considerably less than ideal for intricate chamber music. The acoustical properties of the auditorium, which boom forth the middle and lower registers of the piano, while subduing its upper range (as well as the overtones of the bowed instruments) are responsible for a bizarre series of events leading to the cancellation of at least one concert this spring. (In attempting to compensate the distortion, a female pianist sprained her hand). And thus unhappily, the inner lines of the piano parts, which contain quite a bit of Brahmsian cross-rhythm and harmonic detail, were largely obscured. All violin and cello dynamics had to be raised one level, so that pianissimos were indelicate, and fortes often rasping. The overall result was a rather thick, monotonously undifferentiated texture most of the time.

BUT NOT all the problems of the concert on Monday evening can be blamed on the Business School's new auditorium--which is, after all, given the Harvard artistic milieu, a real sign of progress: no sirens, no uncontrollable drafts, moderately comfortable seats. One can readily forgive a great many performers' foibles--harsh sounds resulting from nervousness, an occasionally self-indulgent glissando, embarassing intonations in enharmonic modulations, ostentatious riccochet bowings which don't synchronize--and so on. But when the composer's written indications of expression are disregarded, and extraneous ones interpolated for the 'luscious' effect of the moment; when the long, harmonically-directed phrases so characteristic of the composer's style are treated squarely, arbitrarily broken in structurally inappropriate places as the result of 'inspiration,' when the intense momentum of an approaching climax is suddenly choked by a needless luftpause--one feels disappointed.

In pleasing contrast to all of this was the lucid, sensitive playing of clarinetist Harold Wright in the best of the three compositions performed. Here was a performer who cared enough not only to master the technical problems for his own instrument, but also to bring forth some sense of the compositional beauty of the music at hand: Brahm's 'honorable mention' for the evening. Dynamic markings were tastefully observed; phrases were si un out to their intended length, and, quite often in dialogue with the cello, passed gracefully to Neikrug, who, taking the opportunity to be heard, broke the continuity with concerto-like attacks. Shure, true to form, continued his discreet nonentity.

One suspects that Mr. Wright's laudable conscientiousness stems from the unfortunate paucity of masterworks for his instrument: those who have little often appreciate most. And one suspects further that Messrs. Totenberg, Neikrug, and Shure would render quite satisfactory performances of any of the 'best-loved' solo repertoire for their respective instruments--Rachmaninoff, Paganini, Bruch, Bloch, Tchaikovsky....Thus it seems that the relevant question to be considered by performers, critic, and audience alike, is: what, by comparison, is a Brahms trio?