Folk groups of an experimental nature proliferated during the 1960s but none was as eclectic as today's Oxymora, in performance three times this past weekend at The Barns at Wolf Trap. Yesterday afternoon the quartet from Shenandoah Conservatory explored, in various combinations of a dozen or so string, woodwind and percussion instruments, periods and areas from the Renaissance to contemporary jazz.

Drawing from Gaelic, Gypsy, Latin American, Appalachian, Baroque and other sources, Oxymora provided a program that combined the bland with the grand. Improvisation, the musicians claimed, played a strong role in their concept, but of several attempts made in this demanding idiom only the polyrhythmic "Mezzyroll" came off as a collective creation. The others were random and meandering.

Although notation was not employed, the major part of the program seemed composed of set pieces, and several of them indicated that this is a group to watch. Perhaps this ensemble takes a while to warm up and maybe needs a more intimate atmosphere than a staged concert permits. But on the final offering, with its flamenco overtones and chilling oboe tremolo, the group really started to simmer.

James Baird, Michael DeLalla and Mark Sims handled the strings (guitars, mandolin and upright bass). Craig Matovich was on oboe, flute, piano and percussion.