Long before computers became a household reality (and unnerving arbiters of consumer credit ratings) they permitted composers to devise pieces using timbres and rhythms virtually unproduceable by musicians on conventional instruments. Last evening's computer music concert at the University of Maryland surveyed the union of the arts and technology.

The rap against computer music is that it is dehumanizing. And when the "performer" is a tape recording of sounds produced by machines, one can see the logic. Yet, the ultimate test is in the hearing; the resourceful composer supplements rather than supplants art with science.

This was evident in Herbert Bru n's "A Mere Ripple," a wave of concentric sonic spirals that emanate much like the proverbial stone tossed into a lake. His "More Dust" fared less successfully; a barrage of gimmicky effects reminded one of a nightmarish Space Invaders revenge in spots.

The high point was Felix Powell's "EBS" ("East By South"), featuring the composer on Synclavir II, a computerized keyboard synthesizer. Lilting percussive figures, reminiscent of a Balinese gamelan orchestra, blended handily with sparkling washes of tonal color.

Man confronted machine to good effect, especially in Wesley Fuller's "Time Into Pieces," as pianist Thomas Moore complemented the smooth brass-like textures of the synthesizer with violent, jabbing chords.