In its first Washington appearance, Pirin, the Bulgarian National Folk Ensemble, seemed quite a few notches above the processed routine we've come, lamentably, to expect in this field. For one thing, there was a constant surge of kinetic excitement, and for another, the folkloric material, both musical and choreographic, hasn't been "arranged" out of all relation to its native roots.

The result is that one's attention didn't begin to lapse after the first few stagefuls of beautiful, hand-embroidered costumes -- a constant feature of these presentations which engages the eye, but quickly palls in the absence of more substantial artistic values.

With Pirin, the accent is not on acrobtics, spectacle, folk pageantry or even virtuosity -- though these are all adequately represented -- but rather on the charm and spirit of the dance and music. In particular, the program underscored some Bulgarian specialties -- wonderfully intricate, syncopated step patterns at blindingly high speeds, embellished by saucy directional flips of the knees and feet.

The collection of native instruments, including the shepherd's flute, bagpipes and rebecs, gave us spicy modal harmonies and piquant rhythms in an unspoiled state, and the reedy sound of the female choir was thrilling. On the dance side, the most effective stagings were those by the troupe's chief choreographer, Kiril Haralampiev, and its resident choreographer, Kostadin Rouitchev.