Curvaceous Concert Venue Ups Ante on Acoustics
Project of the Year & Excellence in Safety Award, Northern California: Bing Concert Hall, Stanford
With complex curves, a cavernous space and demanding acoustic requirements, the design and construction of Stanford University's Bing Concert Hall required a virtuoso performance by the project team.
While the venue houses only 842 seats, its total 680,000-cu-ft volume is actually greater than much larger concert halls, such as the illustrious 2,854-seat Musikverein in Vienna.
The Bing Concert Hall's large volume was required to give Stanford the best possible acoustics for a variety of performances, from a single pianist to full orchestra.
The $112-million, drum-shaped hall is acoustically isolated from exterior sounds within a 12-in.-thick concrete enclosure. "From the very beginning, the university desired an in-the-round room," says Richard Olcott, design partner with Ennead Architects, New York. Incorporating "vineyard-style" seating, the hall features a series of small terraced platforms surrounding the stage on all sides. "There are no straight lines, just organic shapes" in the performance space, Olcott says. "Everything was done with the acoustics in mind."
Nagata Acoustics, Los Angeles, assisted in developing the hall's optimal shape. Nagata's acousticians analyzed as many as 19 design schemes via 3D models. The team used proprietary acoustic software to determine good, and bad, sound reflections down to the millisecond, Olcott says. The nearly 48-ft ceiling height in the hall provides the optimal reverberation, according to Nagata's calculations.
All this precision is "as much about the performers hearing themselves as it is the patrons hearing the performers," says Ennead partner Timothy Hartung. "A lot of the curves, shapes and angles are there for reflection back to the performers on the stage."
The final design called for nine massive reflective acoustic panels, or sails, around the walls of the hall, plus one absorptive panel. Each of the concave sails, as large as 43 ft by 51 ft and weighing as much as 8,000 lb, has a unique curvature, orientation and shape, and was hung at an angle from steel beams tied into the walls.
Tolerances were tight, with even minute deviations from the design having huge potential acoustic impacts. This was compounded by the absence of any square, flat walls to measure from, says Stephen Coates, senior project manager with construction manager at-risk Turner Construction Co., Oakland.
Once the sails were placed in their approximate positions, Turner used laser scanning technology coupled with BIM to ensure precise placement. "We used the cloud point model [from the laser scan] to compare against the design model, and we were able to make our adjustments to get the sails within the tolerances that were required by the acoustician," Coates says. "I don't know how we would have been able to be as accurate as we were without those technologies."
One judge compared the effort to building a water-tight vessel, adding that "installing the acoustic panels without leaking sound in a world-class design is quite an accomplishment."
BIM also aided in building systems and seating design. Angled low walls at the front of each seating section feature textured, wave-like surfaces made from beech wood to diffuse higher frequency sounds. These walls had even tighter tolerances than the sails, with joints no wider than 1/32 in. The panels were attached no more than 3/16 in. from the cast-in-place concrete slabs. With the wall manufacturer located in China, Turner utilized survey data and BIM to communicate with the factory and make subtle adjustments there or at the project site to ensure that everything fit correctly, Coates says.
A curved lobby encircles the hall, flooded by daylight through a 19-ft-high glass and aluminum curtain wall and strategically placed light wells between lobby and hall. The design added colonnades and porticos to connect the interior with a lushly landscaped exterior.
Excellence in Safety