Mining A Diamond

In New York, it's all about building up, up, up. That's why Carnegie Hall's new Judy and Arthur Zankel Hall is so unique: the space is actually down, down, down, below the streets of Manhattan. Or more accurately, below the famed Isaac Stern Auditorium, where it serves Carnegie Hall's vision to provide multi-form performance and education in a multi-configurable arena. To make such a venue fit, the project team had to drill deep down into the Manhattan bedrock. But the results redefine a flexible space: thanks to a series of lifts, Zankel can be transformed into a variety of different configurations — including end stages of various sizes, end stage with orchestra pit, center stage, and flat floor — with capacities of 540-644, depending on the need.

Built in 1891, Carnegie Hall was among the first performing arts complexes with three auditoriums: the Main Hall (now Isaac Stern Auditorium), which has a capacity of 2,804; the intimate Chamber Music Hall, several floors above street level (now the Joan and Sanford I. Weill Recital Hall), which seats 268, and the lower-level recital hall. The latter has gone through several changes over the years but has always served as a performance space, as the Carnegie Recital Hall, a space housing student productions under the moniker Carnegie Lyceum, an off-Broadway space, and finally as a movie theatre.

Once the lease expired on the movie theatre, the powers-that-be at Carnegie Hall decided to take the space back and turn it into something entirely new. And because the space had been compromised both architecturally and acoustically beyond restoration, it was decided that a completely new auditorium be constructed. To help realize their vision, Carnegie executives turned to Polshek Partnership Architects, the team responsible for the Hall's 1986 restoration. The rest of the team on Zankel included Jaffe Holden Acoustics serving as acousticians, Auerbach•Pollock•Friedlander serving as theatrical and A/V consultant, Tishman Construction as the construction manager, and Pook Diemont & Ohl, another participant in the '86 restoration, serving as the stage equipment contractor.

“The owners had a strong, three-point wish list,” explains Polshek design partner Richard Olcott. “First, that the space be intermediate in size, second, that it be totally flexible, and third, that it accommodate the latest in communication technologies.” The resulting design integrates the architecture with an array of technical systems that function as building blocks, facilitating flexible room design using three-dimensional architectural elements.

To achieve the acoustical volume needed for the space, workers had to remove 6,300 cubic yards of Manhattan bedrock from beneath the building, digging approximately 20' below the original theatre floor. Performances continued at Stern Hall during this work, which lasted almost two years. “A mining operation is not an easy thing, especially in Midtown Manhattan,” quipped Robert Harth, Carnegie Hall's executive and artistic director, at the venue's grand opening.

The massive hole, coupled with the nearby 7th Avenue subway line, quickly created noise issues for Issac Stern upstairs. Explains Russ Cooper of Jaffe Holden Acoustics, “There were a lot of issues at that point associated with isolating the construction to the room up above, as well as isolating the big hole that the subway noise could come up through directly to the main hall. We had an opportunity during construction to put in some isolation pads underneath some of the new columns and existing columns that were going to be extended. By doing that, we believe that we reduced the sound of the subway in the main hall pretty significantly.”

The design of Zankel incorporates some of the original brick piers, now encased in plaster, and four of the original cast-iron columns, which extend upward and support the first tier through the balcony of the Stern Auditorium directly above. It became a tight fit in the end, with solid rock often right behind finished surfaces. As a subtle tribute to the intense drilling and excavating portion of the project, a small section of the east lobby wall is actually exposed to reveal the bedrock.

Even before excavation was completed, project team members were onsite. “Long before our engineering and system drawings were complete, we prepared layout drawings of critical lift components coordinated with the temporary shoring columns and future scaffold towers,” says PDO partner Barbara Pook. In March of 2001, PDO's first site work located the north end caissons for the lifts before the south end was excavated. “It was like working in a mine,” Pook says.

“Accurately plotting that many points on such a rough landscape was difficult,” says PDO partner Tony Diemont. “At Zankel Hall we were locating points without finished walls for reference. We were building a puzzle backwards, locating interior components that would later lock many other systems into place.”

Before the excavation was complete, 80 caissons up to 12' deep were located and drilled into the stepped bedrock floor, which were used to support the lifts. The floor level is comprised of a series of eleven lifts, including two smaller lifts within lifts; up to nine lifts facilitate the stepped audience and orchestra pit, with the remaining lifts forming the various end stage configurations. The two lifts within lifts form the center stage in the middle of the room. When used in a flat floor configuration, the lift system allows for easy movement of the chair wagons and other large elements from the storage area located just upstage of the end stage rear wall.

“The overhead rigging was the next piece of the puzzle,” says senior design principal Len Auerbach. “The modular nature of self-climbing trusses was driven by the need to minimize the envelope between the truss unit and the ceiling and to provide the flexibility for required acoustic reflector tuning. Truss modules reflect stage configurations below and respond to the architectural centerlines of the room.”

Zankel's motorized overhead truss system, also part of the stage machinery provided by PDO and manufactured by JR Clancy, is designed to adapt to each of the room's configurations. It is comprised of 21 rectangular trusses, each measuring 7' wide by 12' long, with a capacity of 3,700 lbs and four 40' motorized ladder trusses, which travel 22' from high trim to low trim, and support lighting, sound, acoustic, and scenic elements. In addition, there are four motorized battens spaced between the truss units that can be used for rigging projection screens, draperies, and the like. Both trusses and battens are tied into the master control system and can be operated individually or in groups of three. Because there was no room for a catwalk, all the trusses can be lowered for changes.

In order to work on both the lifts below and the overhead rigging and other systems above, a full scaffold deck with support towers was erected. “There was tremendous demand for simultaneous access to all areas as soon as the dance floor was erected,” explains Pook. “The ceiling is an enormously complex system of new steel framing, electrical work, HVAC, multiple plaster ceiling layers — all of which had to be coordinated around the inviolate locations of the 100-plus telescoping hangers supporting our 25 motorized trusses. PDO generated the primary coordination drawings and worked with each trade to locate their work. No less than two months of constant coordination between the trades precipitated the work on the ceiling. Drawings were overlaid and re-drawn over and over again in an effort to fit every necessary component into the densely packed articulated ceiling.”

A series of 12 stepped wagons and six flat wagons with approximately 410 fixed seats are used to form each audience configuration. Stepped wagons are moved from the storage area to the play locations using an air-casting system that allows the 5,000 lb. wagons to hover above the floor and be moved into position by the Zankel stage crew. The smaller, lighter flat wagons are transported on a series of tri-casters to their play positions. Each wagon is pinned into place on the lift floor and registered with a centralized master control system. The chair wagons are part of the stage machinery provided by PDO; the seats were manufactured and installed by Theatre Solutions Inc.

“The process of getting everything to fit in the room was certainly difficult,” says Len Auerbach, “but the greatest challenge of the project was working out the dimensional tolerances between lifts and associated wagons that play in more than one position. The dimensional criteria for these items were much smaller than ‘typical’ construction tolerances.

“An additional challenge was finding creative ways to move and store all the wagons, seats and other elements when the hall is used in its flat-floor configuration, or when it is turned over from end stage to center stage configuration,” he continues. “When the room is used for flat floor, the storage area upstage is packed with stepped wagons, flat wagons, seats on skids, railings, step units, etc. That's stacked two rows deep, three levels high. In the transition from end stage to center stage the entire lift area plus the storage area is used for module cueing and maneuvering as the keystone shape of each wagon dictates a set choreography. Anyone who has packed a truck for tour will be familiar with this kind of drill.”

The finished space consists of interlocking geometric forms in contrasting materials, containing two seating levels, parterre, and mezzanine. Placed within the rectangular outline defined by the footprint of Carnegie Hall's masonry-bearing walls is a canted ellipse constructed of reinforced concrete. Nested in the ellipse are four freestanding walls which help define the acoustical volume. Outside the auditorium, the ellipse is finished in finely polished artisan plaster; its curvature leads the audience around to each point of entry to the house.

The acoustical elements of Zankel were, needless to say, critical to the success of the space. “We looked at the first classical music concert halls from the 18th century in England and Germany,” Jaffe Holden principal Chris Jaffe explained at the hall's press preview. “They had qualities of transparency and warmth, with small audiences. The keys to these spaces were that they were rectangular, with a certain volume, and rich reflective energy patterns.” The rectangular shape of Zankel, lined with 3/4" American sycamore wood on the walls and maple on the floor, was influenced by those earlier spaces; the fact that this rectangular shape is housed inside an ellipse “gets rich reflections,” Jaffe said, “and provides a sense of comfort for the musicians — they can hear themselves.”

Still, Jaffe Holden were faced with two major challenges: not only Stern Hall directly above, but the 7th Avenue subway. The former was accomplished by acoustically isolating the two venues from one another. “We designed a double plaster ceiling,” Cooper explains, “two layers of plaster with an air space between where all the duct work and utilities go. Each ceiling is 2" thick, with a 2' air space, and it's all suspended on a steel system that rests on rubber pads from the existing girders of Carnegie Hall. From the loudspeakers suspended from Zankel to someone sitting in a seat at Carnegie, is probably about 4'. And by all accounts, it's been successful.”

Isolating the subway from Zankel has proven more challenging; the track was laid directly onto the bedrock, and is only about 8' from the wall of the lobby. “We did some measurements and discovered this is a 35dB difference compared to what it was before, but it's still an issue,” says Cooper. “It's an ongoing project.”

The performance systems in the space are geared to ease of use. “Zankel Hall is designed so simple concerts and recitals can be operated by one person,” explains house lighting designer Alan Adelman. “Once a stage configuration has been established, basic lighting, video projection, and the audio functions can be cued by a single stagehand from a backstage location near the USR access door to the stage.”

“The greatest challenge of the performance lighting system was accommodating and coordinating a great deal of infrastructure in a very tight space,” says Auerbach associate Grace Gavin, project manager and project designer for the theatrical lighting systems. “Take a glance at the ceiling truss units, loaded with lighting and sound equipment, and the enormity of the task is clear. Exhaustive efforts were required on the part of the design team as well as the multiple construction trades to ensure that not only the lighting but all of the performance technical systems were installed to the highest possible standards.”

The Ethernet-based lighting system, designed to control conventional, intelligent, and architectural fixtures, features ETC Sensor SR24 and SR48 dimmer racks, two Expression II consoles, ETC Net2 access points, with an ETC Unison system controlling the architectural elements. The lighting plot, designed by Adelman, features ETC Source Four 36 degree ellipsoidals and Source Four PARs, City Theatrical AutoYokes, L&E ministrips, Robert Juliat Ivanhoe followspots with DMX control, and Vari*Lite VL1000 automated ellipsoidal reflector spotlights with tungsten lamp and shutters and VL5B luminaries. Fourth Phase served as the system contractor for the lighting, with gear coming from 4Wall Entertainment East.

“There's no way to get ladders out to some of the positions when the room is in various configurations,” explains Adelman of the inclusion of the Vari-Lite units. “That was one engine driving the train. The other was that the units had to be totally silent in a static, focused position, with no fan noise. For this kind of lighting, the VL1000s are great fixtures. They are accurate, silent, and very effective because of the zoom range, shuttering, and color mixing capability.”

The sound, video, and communications systems, designed by Auerbach principal Paul Garrity (with associate Daniel Mei), needed to be as flexible as the space itself. “Working with an auditorium that is primarily for live acoustical performance,” Garrity explains, “we needed to provide a flexible system design that could address the needs of sound reinforcement, surround sound, broadcast, and distance-learning playback, while ensuring that the system would be easily set up and operated. Of course, the system had to sound great and it had to be as visually unobtrusive as possible — a neat trick in a room that can be reconfigured from end stage to center stage.”

The mainstage end arrays consist of Meyer CQ-1 and CQ-2 self-powered speakers and USW-1P subwoofers, with UPA-1Ps as auxiliary end stage and additional center stage arrays. Meyer UPM-1Ps also serve as portable stage edge speakers, with UM-1Ps and UM-100Ps as portable stage monitors. The space is controlled by a newly arrived Yamaha PM5000 console, which complements the existing PM1D digital console. “Our decision to purchase the PM5000 was based on our positive experience with the PM1D,” explains house sound engineer John Cardinale. “We also felt that the PM5000 would provide guest engineers with the latest technology and greatest flexibility, along with the familiar PM series configuration.” Cardinale uses a PM1D in both Isaac Stern and Zankel Halls.

Other reinforcement gear includes a Yamaha MV12/6 secondary mixer, Meyer CP-10 dual parametric EQs, BSS Soundweb 9088ii digital signal processing, and a microphone package featuring AKG, Audio Technica, Countryman, Crown, Neumann, Sennheiser, and Shure. The communication system features a Williams Sound PPA-T4 assistive listening system, and a Clear-Com intercom system. In keeping with its focus on education, Zankel also features a distance learning and broadcast system incorporated into its infrastructure, enabling current and future distance learning simultaneously with offsite performance venues as well as potential webcasting. Andrews Audio served as systems contractor.

Zankel Hall opened in September with a concert highlighting the work of composer John Adams, with music by Charles Ives, Thomas Ades, and Esa-Pekka Salonen. Over 80 events are planned for the 2003-2004 season, ranging from new music by Adam Guettel for Audra McDonald to a mini-festival highlighting the work of Emmylou Harris to a wide variety of jazz, world music, and chamber music concerts. Such a versatile lineup underscores the collaborative nature of Zankel's mission, and is also reflected in the work of those who designed and built the space.

“The complexity of meeting the program of activities within the proscribed architectural envelope turned up our juices and further underscored our highly collaborative relationship with the Polshek Partnership and the participants from Carnegie Hall,” says Auerbach. “There are technical solutions to most every requirement, but it is the clear understanding of integrating the aesthetic, functional, and programmatic aspects with the application of the appropriate technology that challenges the creativity. Zankel Hall is a wonderful example of succeeding on all fronts.”