The instruments and sounds that seem at first to not fit into the Wandelweiser world come from strings—a bowed note held continuously until the musician can no longer perform the stroke. Yet Frey has written marvelous string quartet music that contrasts the inherent delicacy of silence with careful, concentrated string playing. The great Bozzini Quartet has recorded all of his string quartet pieces so far, this colorful, fiercely quiet performance being the most recent.