Louise M. Davies Symphony Hall - Acoustics

Acoustics

Designed by Skidmore, Owings & Merrill and Pietro Belluschi along with acoustical consultants Bolt, Beranek and Newman, its modern design is visually elegant both inside and out. A “cloud” of movable convex acrylic reflecting panels over the stage enables the acoustic space to be adjusted to suit the size of the orchestra and audience, while adjustable fabric banners around the auditorium can alter the reverberation time from approximately one to two-and-one-half seconds.

Acoustic isolation of the performance space was obtained by constructing a building within a building. The outer building uses one inch thick structural glass as a curtain wall, with the next structural wall forming the back wall of the lobby spaces. Passing through a door leads to a hallway, bounded on one side by the lobby wall and on the other by the structural wall of the inner building. This continuous hallway acts as an acoustical isolator and is surfaced with sound absorbing material.

However, the hall's large volume and seating capacity initially resulted in less than ideal results. Acoustical renovations under the direction of Kirkegaard Associates were completed in 1992 at a cost of US$10 million, resulting in substantial improvement.

The modifications included narrowing and shaping the walls above the stage to reduce the volume of space and increase useful reflections, replacing the cloud of reflector discs with a more effective array that covers a larger area and is computer adjustable, pulling in the walls of the floor-level seating to make the audience area narrower and more rectangular, adding aisles to replace the former continental seating, adding diffusing elements in various parts of the hall, and increasing the “rake” of the floor seating to provide better sightlines. In addition, risers were installed on stage to allow the musicians to both see and hear each other better. These and other improvements enhanced not only the acoustics but also the hall's beauty.