There has been a tendency in recent years, due to the immediate surface appeal of works like "Appalachian Spring," to accuse Aaron Copland of superficiality. But the three works presented in Sanders Theatre Wednesday night indicate that Mr. Copland is also capable of creating music of elusive profundity.

The concert opened with the acid sonorities of the Quartet for Piano and Strings. Instead of the usual Coplandesque breadth of expression, there is a depth in this work, a concentration of latent forces than cannot be grasped at first hearing. It will probably be a long time before the work is fully understood by the musical public. There seemed to be certain errors of judgement in the piece however: the uninteresting piano writing in the first movement, the curiously out-of-place whimsicality of the second, and the thin, widely spaced, unpleasant harmonics near the end.

Copland's settings for twelve poems of Emily Dickinson were especially enjoyable because they were sung by Katherine Hansel, one of the finest vocalists to appear in Cambridge in months. A soprano, her wide range made her sound at home even in the lowest alto registers. She has a surety of pitch that enables her to make skips of as much as two octaves without noticeable effort. Add to this her spacious tone and fine powers of interpretation, and the result is a singer who would make even bad music sound good.

But Copland's songs are far from bad. Once in a while he sank to the cliche of repeating the first lines at the end of the song, thereby destroying the calculated effect of Dickinson's stanziac form; but on the whole, his settings agreed perfectly with the words. The composer's own playing of the accompaniment made the songs even more enjoyable.

The Sextet for String Quartet, Clarinet, and Piano is a more accessible work than the Piano Quartet because of its greater rhythmic vitality and harmonic familiarity. Masculine, direct, and always moving, it is more in the old Copland tradition. The Juilliard Quartet and pianist Lconid Hambro played excellently, but David Oppenheim wasn't up to the technical demands of the clarinet part. LAWRENCE R. CASLER