Moving The San Francisco Opera Is A Big Production
System Contractor News      March 1997
by Dan Daley

This was not a rock opera, although the elements of both kinds of music were quite present on a September evening last year. The crowds were lined up outside the Bill Graham Civic Auditorium, the city's venerable rock music and general purpose venue. However, inside the venue it was decidedly black-tie rather than tie-dyed, with the attendees anticipating the overture of Borodin's "Prince Igor" by the San Francisco Opera.

Under normal circumstances this toney crowd would have gathered at the city's War Memorial Opera House, as they had for the last 64 years. However, the opera's normal venue was closed temporarily for renovations including (this being San Francisco) seismic retrofitting. Taking the opera out of its usual setting is no small task -- unlike other live performance arts, opera has historically relied upon acoustically precise environments rather than sound reinforcement for projection and articulation. The Civic Auditorium, designed for mass gatherings like conventions and rock concerts, is proficient in neither. It was, however, available, and for the temporarily peripatetic opera company, that was good enough for the moment.

"The entire process was one of compromise," explains Roger Gans, sound designer for the San Francisco Opera for the last 15 years. Gans, who is responsible for sound effects and other prerecorded audio elements for the company, understated the need for compromise elegantly: "Amplification is frowned upon in opera. It's an art form that requires a truly acoustically precise space, which is not something that you find in a large convention hall."

Fortunately, Gans had two years' notice to begin planning for the company's temporary homelessness, and in conjunction with Meyer Sound Laboratories was able to bring an unparalleled degree of acoustical realism to the Civic Auditorium using sound reinforcement.

Working with Meyer engineers, the Opera's stage designer and consultants from Paoletti & Associates, a leading San Francisco acoustical firm, Gans chose an array of Meyer components, including Meyer UPL-1, MSL-4 and recently introduced Meyer CQ-1 and CQ-2 self-powered systems. Based on initial calculations, they were hung in three rings around the hall's thrust stage: Five UPL-1 speakers are installed at ground level on either side of the stage; a flown ring consisting of a Meyer CQ-2 in the center surrounded by four CQ-1 speakers provide coverage for orchestra seating up through the auditorium's box seating; the balcony level is covered by clusters of self-powered Meyer MSL-4 speakers. In addition, the room is further filled with six more CQ-2 speakers as a surround system, which, using T.C. Electronics digital DDLs, delays the main signal by approximately 25 ms. at the orchestra level to provide a recreation of the fast early reflections that would normally be heard in an acoustical operatic setting.

This approach is described by Meyer Sound president John Meyer as "a virtual wall" of sound -- We're using three CQ-2s on each side of the house to create the early reflections audiences are used to hearing at the War Memorial Opera House," he explains. "The effect is subtle but important. We're doing everything we can to bring to the music to the listeners as they're used to hearing it."

The San Francisco Opera plays a large role in the development of the new Meyer CQ Series of speakers. According to Bob McCarthy, director of technical support for Meyer, the new system was intended for the Opera house once its structural renovations were completed. "The architectural requirements of the Opera house caused us to create an entirely new system for them," he explains. "We had first intended to use the MSL-4 system, but the new design of the venue called for a different kind of enclosure. The CQ system has a lower Q [directional control] than the MSL-4. In developing it, we embarked upon an extensive survey of horn design. The Opera needs a completely transparent-sounding, classical-level of sound reproduction. So we tested every type of horn ever made -- including designs that date back to the 1930's -- in an anechoic chamber, measuring them in 1/24ths of an octave. No one had ever analyzed those horns so intensively before. In four months we developed a system with a truly constant Q that holds its directionality consistently both on a horizontal and on a vertical plane. In this case, the CQ-1 provides 80 degrees horizontal and 40 degrees vertical coverage at -6 dB points and 100 degrees horizontal and 50 degrees vertical at -10 dB points, and the CQ-2 provides 50 degrees horizontal and 40 degrees vertical at - 6dB points and 60 degrees horizontal and 50 degrees vertical at -10 dB points. And both loudspeakers accomplish this with a frequency response of 40 Hz to 18 kHz at four dB. It took a year to fine-tune the CQ, but we developed what was needed. Then came the temporary move to the Bill Graham Auditorium, and that gave us the opportunity to beta-test the system with the Opera itself. And the results have been everything we expected them to be."

The new modularly designed Meyer CQ ("Constant Q") self-powered speakers, like other Meyer self-powered components, include an amplification system optimized for the cabinet's load of drivers, as well as control electronics featuring Meyer Sound's Intelligent AC™ system, which performs automatic voltage selection, EMI filtering, soft-current turn-on and surge suppression.

The Opera installation marked the debut of another new product, Meyer's Remote Monitoring System. RMS™ is a computer network that interfaces with all Meyer self-powered speakers and constantly scans major speaker and amplifier operational parameters, indicating the location of any problems, such as a blown driver or overheated amplifier. According to McCarthy, "The benefit of the RMS in the Opera House, or any other installation where speakers are flown, is that it replaces visual and auditory inspection of the sound system. With it, the sound system stays at maximum functionality as originally installed and SIMed."

After the speakers were hung in an approximation of their ultimate positioning, Gans and Meyer technicians used the Meyer SIM® acoustical analysis system to analyze the space. "This was not the time for experimentation," recalls Gans. I had used all of this Meyer equipment before, so I had a good idea of its capabilities. All of the rigging was designed so that we had plus or minus ten degrees of play in the positioning of the boxes, with heights and angles laid out on a CAD system. All of the rigging had to have flexibility so that we could adjust the angles based on the results we got from the SIM."

They utilized B&K microphones in various positions and pink noise curves from the SIM system in an effort to establish horizontal and vertical zones of coverage, finding the edges of each zone to create a smooth sonic and frequency transition between each zone. "What helped enormously was that these Meyer speakers have very predictable coverage patterns," says Gans. "It's a precise, meticulous process, aiming one speaker on-axis and the next off-axis to establish the overlap areas. But if you get a good [SIM] reading and have a protractor, you can lay a system out accurately. It's like lighting: you can point the speakers in the direction you want and get good results. The next order of business was to set up the microphones. "The general director [of the Opera] told me right from the start that he didn't want [wireless] body microphones," says Gans. I was prepared to try that and wanted to push the use of wireless mics to the next level. But there's a certain stigma attached to using microphones in the opera."

The result was a grid of B&K cardioid microphones suspended above the stage in a carefully programmed pattern, done in zones similar to that of the speaker arrangement, designed to adjust gain levels to the movements of the vocalists. "The spacing was intended to have one zone trail off immediately upon entering the next zone so as to avoid phase cancellation between zones," Gans explains. "It's the same principle as the way the speaker systems are set up -- the same avoidance of overlapping patterns needs to be addressed." To enhance the effect of natural attenuation and the distinction between microphone zones, the dynamics processing -- specifically a gentle setting of the expander -- of a Euphonix CS-2000 digitally controlled analog console was used to accomplish this. "We needed to drop the overlap shadow between zones by at least six dB, which the cardioid microphones and their placement helped us do," says Gans. "Using the the expanders we were able to get a few more dB."

Finally, Gans and company inserted EQ into the system using Meyer CP-10 parametric equalizers -- one for each of the 21 speaker zones (using 33 Meyer speakers) established -- as room EQ. These were to compliment the acoustical treatment that had been added to the Auditorium's walls, including absorptive treatment to the room's back wall and rigid material attached to some of the production stage sets which would acts as a side diffusor. The seating areas were also carpeted and the seats themselves were padded.

But the heart of the system was the Meyer components, which Gans had effusive praise for. "The self-powered components provided a major advantage in that we did not have to deal with amplifiers, signal processing beyond the EQs and crossovers. All of the signal processing and speaker control is already optimized, so there's no further coloration of the sound. We went with the Meyer components for a lot of reasons, but one of the main ones was, we knew what they would sound like before they were in place -- they are quite consistent in sound and precise in their coverage. In particular, the new CQ speakers are very accurate. In a situation like this, having the ability to point and shoot with the speakers helped us get a good sonic environment quickly. And that made all the difference in the world."

And as John Meyer adds, "Listeners don't realize all the work we're doing. And that's the point -- they shouldn't have to. What we've done here is advance the art and science of sound to recreate an old-fashioned ideal: a night of wonderful opera."