San Francisco’s Davies Hall is “tuned” for every performance. The computer-controlled acoustical canopy that dangles over the stage looks like some huge constructivist sculpture and reflects sound back to the musicians and out to the audience. It’s composed of 59 slightly bowed 6-foot squares of Plexiglas – they collectively cover 3,400 square feet – whose height and angle are adjusted according to the size of the ensemble or to the piece being performed.”