THEATRE IN THE ROUND

Jun 1, 2000 12:00 PM, David Drommond

Utah is well known for its snow, spectacular National Parks and cultural attractions like Temple Square and the world-famous Mormon Tabernacle Choir. Now, there is a new cultural attraction in the Salt Lake Valley that is drawing rave reviews - a performing arts facility that has been called "the finest center-staged theatre in the world."

The Hale Centre Theatre in Utah's West Valley City has won architectural awards for its unique design, and it is winning theatre patrons in droves for its brilliant combination of high-tech staging and intimate atmosphere. A key component of the success of the theatre's design is the sound system, which serious theatre fan Neal F. Bradshaw describes as the best he has ever heard. Neal's opinion carries some weight because he is the senior designer and group manager of the architectural division for the LDS Church. He has experienced sound systems in hundreds of buildings and theatres. Creating the sound system that would complement the Hale Theatre's state-of-the-art design presented some interesting challenges that will be addressed in this article, but before getting to the nuts and bolts of the sound system, let me set the stage for you.

More than $7 million was invested in the construction of the Hale Theatre; that it was money well spent is evident at first sight. The exterior is a neo-traditional design that invites the eye. An approach after dark is especially pleasing because of the accent lighting that graces the building from top to bottom. The exterior design disguises the mass of the building, which houses a main theatre, four rehearsal halls, eight dressing rooms, a kitchen, concession stands and extensive costume storage.

Inside is a traditional grand staircase leading to the second level. Chandeliers, wood trim, stained glass, and special lighting contribute to an atmosphere of warmth and intimacy. The main theatre seats 531 people around its center stage. Eight rows of seats on risers arranged in an octagon guarantee that every person has on unobstructed view of the performance. Competing with the actors for attention is the stage itself, a unique design costing about $1 million. Multiple platforms can raise and lower independently of one another over a range of 16 feet (4.9 m) and can rotate in both directions while the center platform rotates in the opposite direction. Revolutionary computer technology controls the stages, lights and sound system.

Speaking of which, the sound system has become a more critical component of the modern performing arts facility. Audiences, increasingly sophisticated, expect a high-end concert-hall quality of sound experience. To provide anything less would significantly reduce the perceived value of the entire Hale Theatre experience.

Slaying acoustic dragons

The acoustic challenges at the Hale Theatre were significant, to say the least. The building is located less than a mile from the Salt Lake International Airport glide path, about a hundred yards (91 m) from Interstate 215, and is fronted by a busy concrete-surfaced street. Let us review what was done to slay these acoustic dragons, starting with the exterior of the building.

In days of yore, dragons were slain by knights. Acoustic dragons, however, are slain by acoustical consultants. Acoustical consulting involves an understanding of physics, acoustics, electrical engineering, and plain horse sense. The environmental noise elements mentioned above required that we use all of our knowledge and experience. Sound Design International consulted with the other members of the design team for the design and construction of the Hale building as well as the choice and placement of the sound hardware.

Noise from incoming and outgoing airplanes presents a special challenge because the noise source changes in both volume and pitch. In a quiet environment, an approaching airplane gets louder and its frequency (pitch) changes. As a plane flies over, the pitch changes, but the noise abates back to the quiet setting. This movement from quiet to loud to quiet, along with the pitch change, creates the noticeable, unwanted condition.

Although the airplanes were a major nuisance, the freeway was an even greater concern. This type of noise source is a line radiator; the noise drops only 3 dB per doubling of distance. In comparison, a point source drops 6 dB for every doubling of distance (inverse square law). Unfortunately, we could move neither the freeway nor the building.

Compounding the problems with the airplanes and the freeway traffic was the cement-surfaced street that passes in front of the theatre. A car or truck driving on cement creates more noise than on asphalt, and the noise of emergency vehicles screaming past the hall cannot be tolerated inside. These conditions provided still another source of random changes in loudness and pitch.

After studying, measuring and carefully calculating, we requested an EIFS (exterior insulation finish system) on a block wall with the cells filled with sand, the outside sealed with a heavy paint and the inside finished with two layers of sheet rock. Further, the orientation of the building was changed so that the front was not directly facing the freeway. This allowed for the directional noise to glance off the walls, reducing the penetration of offending sounds. Windows and doors are the weak points to a high transmission loss boundary. We requested a reduction in the size of the planned windows, the addition of multiple glazing, and vestibules for the doors - all of which really helped our cause. Finally, the roof also received acoustical attenuation to create a uniform sound barrier from the unwanted exterior noise. The proper noise shield was provided by roofing materials, insulation filling the void and sheet rock.

The interior

Taking care of the exterior noise was only the beginning. The interior of the building also presented some interesting challenges. The design goals mandated that every discipline would help to increase the intimate feeling of the theatre. The room was designed for the best possible acoustics before the sound-reinforcement system was even considered. Our design required an angled rear wall and an angled ceiling behind and above all the seating for the best early reflections into the audience area. By doubling the sheet rock on the angled rear walls and ceilings, the base energy is retained in the space.

The interior design has some positive and some negative features for noise. The walk-about corridors surrounding the main theatre are a blessing. This area adds to the isolation to keep both externally and internally generated noise from getting into the main hall.

At our request, the mechanical engineer responsible for the building's heating and air conditioning used fiberglass-lined ducts, multiple 90 degrees duct angles with turning veins and low-velocity air flow from the system into the theatre. This system under full load is totally unnoticeable in the room.

The cupola above the main stage (fly loft) had to be treated with absorptive material (6 inch or 152 mm black fiberglass batts) to keep the natural sound from the stage from being dumped back onto stage as a discolored echo. During construction, similar absorptive material was also installed in the orchestra pit walls to reduce the noise created by the stage motors and prop handling.

Because of the high water table on the property, a water pump was required in the basement. A submersible unit was used so that pump noise would not propagate into the theatre stage area.

Controlling exterior and interior noise is important and the entire design and construction team cooperated with our directions to maximize noise abatement in their areas of responsibility. On the other hand, controlling noise is only half the battle. The other half is to design and install a sound system that meets high expectations for quality while accommodating the special requirements of theatre in the round.

The sound system

Theatre in the round requires a unique approach to sound-system design. Unlike a normal theatre where the actors are usually working from the stage, theatre in the round actors can be anywhere - the main stage, the auxiliary stages, even in the aisles. Sound reinforcement is required everywhere.

A tough thing to do is to get an ears-in-the-theatre mixing location. People who are not well informed often think that the mixing board should be placed in the theatre by eliminating a paying customer's seat. The architect accommodated the sound control system rather well by putting it in a great location with lines of sight to every part of the theatre. Operational noise (from equipment or rigging) is cut off from the noise-critical part of the control booth by a wall and a door. Sometimes the worst critics of a sound system are the operators, but not in this venue. The operators at the Hale Theatre are capable engineers and were involved on the design team from the beginning.

The Hale Theatre sound system consists of 72 mic inputs in the catwalks, stages and pit; a 48 input mixing console (Allen & Heath GL3300), computerized program hard disk storage, 16 AKG WMS-300 wireless mics and a Rane RPM26V DSP (digital signal processor) for broad and narrow band filtering. The amps, consisting of Crown CE 1000, CE 2000 and K-2 units, are all placed together but distant from the mixing location and theatre to keep the fan noise from disturbing the audio engineer or the audience.

The optimum main house loudspeaker design would have been a central cluster. In our case, the compromises that plague every design required the loudspeakers, mostly JBL SP212s, to be installed in an exploded cluster array. This compromise was necessary because the fly loft over the stage is as large as the main stage. The loudspeakers could not interfere with the scenery being lifted from or dropped into place. The bottoms of the catwalks were the next best location for the loudspeakers.

After the direction had been determined, loudspeaker selection, location, direction and rotation were engineered. EASE (Electro-Acoustic Simulator for Engineers) and EARS (Electronically Auralized Room Simulation) were used to verify that the design was correct and to tweak the coverage angles. These computer programs are powerful allies. They permitted us to model and virtually listen to the room and sound system before the hall was even constructed. Like any tool, the programs are only as effective as the operator. Experience is the key. In inexperienced hands, they can lead to some poor decisions about system design and layout.

Where to install the subwoofers? From the front row of seats to the stage floor is only one step; there is no room on the floor. Flying the subs, EAW SB150Rs, under the catwalks would not be as effective as having a large, acoustically hard surface with which to couple, so the ceiling was chosen. The subs were installed touching the ceiling as high up as the ceiling would permit. This increased the subs' efficiency by creating a sound pressure wave strong enough to shake the audience and add to the realism of the productions. If you want thump, you get thump.

Three special-effects loudspeakers were placed at every entry on the main level and 10 on the second level. This setup permits sound effects that are limited only by the director's imagination. A train can be sent racing through the room, or you can hear rolling thunder that is so realistic it makes you want to dive under the seat.

Loudspeaker outlets were installed on the main stage and also on the three auxiliary stages to feed program material to the loudspeakers placed under an old phonograph, telephone, television or other props. This allows for these special effects to be cued and controlled from the sound booth.

The main system was balanced and equalized with the use of two valuable tools - a SmaartPro analyzer program and two human ears connected to the powerful gray-matter computer that sits between them. No amount of advanced technology can replace the natural hardware with which humans have been blessed.

The electrical engineer provided an isolated ground for the sound system power with a TVSS (transient voltage surge suppressor). This measure helped to keep all the electrical noise out of the sound system.

Moreover, the theatre operator wanted to be able to pre-record a show's sound and music on the sound computer, record all of the lighting cues on the lighting computer, store all of the motorized stage cues on its computer and then tie all three systems together. This arrangement requires only one person to man the control booth. Manpower and the need for coordination were reduced, but it does place a lot of responsibility on one person.

Other electronic components included in this project were the paging/alert system, CCTV (closed circuit television) system (a Blonder Tongue unit with Philips CCTV cameras), the theatrical intercom system (ClearCom WBS), and the assistive listening system (Williams Sound PPA 250E transmitter and PPA R7E receivers). From the ticket office or the control booth, all call or zoned tones can be generated to call the patrons back from intermission or to cue the actors. Loudspeakers are even installed in the restrooms. This same system is also used for paging at times other than during a performance.

The CCTV system has a camera in the main theatre with televisions in the fireside lounge, administrative offices, ticket office, rehearsal halls, green room, lighting booth and pit. Most of the televisions are used to cue the staff and actors, but the television in the fireside lounge is for the patrons who arrive late. They can watch the production in this room until intermission and then take their assigned seats without interrupting others. Now if we can just get them to turn off their pagers, telephones and watches with alarms.

The project was a great opportunity to work with some professional and talented people. By cooperating and coordinating our efforts, the design and construction teams were able to create a world-class performing arts facility whose beauty and technological features make it a major gem in the cultural diadem of the Salt Lake Valley.

If ever you find yourself in Salt Lake City, plan to attend a production at the Hale Centre Theatre. Successful theatre, it is said, depends upon the audience's willingness suspend disbelief. Perhaps so, but when the director cues the cannon-fire light and sound effects in the Hale Theatre, I guarantee that you will be reaching for your helmet.