The David Friesen Ensemble, at Blues Alley last night, is proof that a chamber group of strings that draws from exotic musical sources can generate combustion. Friesen, long an acknowledged virtuoso of the upright bass, now uses an Oregon bass, a tall, solid wood electric instrument of recent design that very nearly achieves the tonal quality but lacks the aged wood resonance of its acoustic parent.

A variety of moods was produced by the six originals that made up the opening set, from the rather formal Japanese court music impressions of John Stowell's mandolin on "As The Day Begins" to the funereal "Seven Cities" to the gypsy dance movement of "Descending Dreams."

Textures were dense and the polyrhythms complex as Stowell applied fingers to kalimba (African thumb piano) and sticks to cymbals and blocks, and Paul Patterson, on 12-string guitar, engaged the leader in dialogue.

"In the Place of Calm," which closed the set, was only the calm in the eye of the hurricane; the number built to a gale force improvisation with Stowell first on electric guitar and then on percussion, Patterson alternately on violin and 12-string guitar, and the leader picking, strumming, double-stopping and producing whining glissandi in a tour-de-force display of passion.