Continuing Education: Margot and Bill Winspear Opera House
When size matters: A hall reproduces old-world sound in a larger modern setting.
An overarching goal for the design team behind the new Margot and Bill Winspear Opera House in Dallas was to re-create the experience found in some of Europe’s much-loved opera venues. One of the Winspear models was the Classical-style, horseshoe-shaped hall at Munich’s National Theatre (1818). The sought-after acoustical qualities were strength, intelligibility, and warmth, says Bob Essert, director of Sound Space Design, the project’s acoustician. “The objective was to envelope the listener with orchestral sound while maintaining the clarity of the singers’ voices,” he adds.
One important factor for opera is a hall’s size. Since the medium depends on the power of the human voice and of instruments to “excite” the room without amplification, “smaller is better,” says Essert.
However, the Dallas venue is larger than its European predecessors. Munich’s early-19th-century hall, rebuilt substantially according to the original’s plans by Karl von Fischer after a World War II bombing, holds almost the same number of people as the 2,200-seat Winspear. But despite comparable capacity and a similar horseshoe layout, Dallas is about 25 percent bigger due to current codes and patron preferences, says Richard Pilbrow, founder of Theatre Projects, a Winspear design consultant.
To create a sense of visual and acoustical intimacy at Dallas that belies the hall’s size, Foster + Partners and its consultants carefully adjusted the five levels to make the configuration as compact as possible and manipulated finishes and geometry. The perimeter walls and the balcony fronts are fundamental to this strategy: A rough plaster coat covers the concrete block walls, while the balconies include a wavelike relief pattern in glass-fiber-reinforced plaster. These surfaces, together with slightly convex profiles, help evenly disperse sounds, especially those at high frequencies, between 3,000 and 6,000 hertz. Sounds in this range are key for the transmission of consonants, explains Essert.
The team also needed to consider ambient noise, such as the hum of mechanical systems. To minimize such potentially distracting sound, designers located equipment in remote areas of the building, specified attenuation in ducts, and opted for displacement ventilation. Because the system introduces cool air from below the seats at low velocities, it operates more quietly than one that would rely on forced air from above.
The Winspear sits not far from a busy freeway, so noise from the exterior environment was also a concern. While the lobby surrounding the auditorium provides some protection, its glass enclosure includes an 84-foot-wide section that opens to Sammons Park, thereby compromising the space’s ability to act as a buffer. To compensate, the walnut doors on either side of the “sound-and-light lock” between the lobby and the hall were thickened to 3 inches. And to prevent the sound of jets taking off and landing at nearby Love Field from penetrating the auditorium, the penthouse above the stage has three layers of smoke-evacuation hatches, instead of just one or two.
Although the Winspear was conceived primarily for opera, it will also host other types of productions that might depend on amplified music. To allow the “drying up” of the hall for those instances, Theatre Projects devised a retractable banner system that follows the curve of the perimeter walls. When deployed, the curtains shorten the room’s reverberation time without changing its fundamental architecture.