The performing arts center has a theatrical performance on Tuesday, a rock show Thursday, symphonies Friday and Saturday, and a jazz quintet Sunday – with ballet and opera the following week. Everything from spoken word to recorded accompaniment to live music is reproduced by the loudspeaker system(s), and with the price of tickets, the sound has to be clear, full, and intelligible.
The quality of what the audience hears is critical to their experience of the artistic performance, with focus on seeing and hearing rather than eating, drinking, dancing, and socializing. In addition, touring artists want to sound their best, and part of the decision on where they play is based on the quality of the audio system and the reputation of the venue.
These facilities may be purpose-built, with acoustical properties considered in the architectural design, or it may be an historical building converted into a performance venue – such as a church, armory, cinema, or courthouse. In all cases, the end result of the audio installation must accomplish specific goals.
All of the seating areas should have decent sight lines to the stage, and the audio reproduction at each seat should have a minimal variance in level and frequency response – always a challenge. Depending on the type of performance, sound levels have to vary from intimate for spoken word or a theatrical performance to powerful with plenty of low-frequency energy for contemporary music.
In many installations, a main left/right system is flown which can be run in either stereo or mono; a center cluster or array may also be involved in larger halls, with an additional central system for announcements. To project with relatively even level to the back of the venue, and to balcony and underbalcony seating, the delay settings and levels of various elements of the loudspeakers can be adjusted to provide longer throw to the more distant seats, with careful consideration of the coverage overlap between adjacent cabinets.
The challenging coverage environment presented by Opera Hall at the Segerstrom Center for the Arts in Costa Mesa, CA. (click to enlarge)
Alternately, additional distributed and delayed loudspeakers can be utilized to cover seating areas shadowed from the main array, or for venues that are so deep that the throw from the mains must be supplemented. Unobtrusive front fill loudspeakers often cover the very front rows.
Venues that present primarily acoustic music may want the loudspeakers to be especially unobtrusive, retractable, or portable. This implies that it needs to be easily deployed, set up and removed from the stage area. Some venues impose strict aesthetic guidelines, requiring loudspeakers to be concealed in some manner – covered by a scrim and/or built into soffits.
David W. Robb, senior associate at Acoustic Dimensions (Dallas, San Diego, New York), often has the opportunity to become involved in the early design stages of performing arts centers, consulting with architects on new builds and major renovations. He states that “there is no such thing as perfect acoustics for all purposes” since performing arts centers are almost always multi-purpose, so it becomes a compromise that hopefully favors the dominant use of the space, with the flexibility to make adjustments.
David W. Robb of Acoustic Dimensions. (click to enlarge)
Key questions: what is the maximum SPL required in the space based on audience size and placement, and the types of performances expected; how visible or concealed will the audio systems and rigging need to be; where are structurally sound rigging points located; where will all of the various systems’ electronics be located, and the signals distributed?
Robb’s ideal performance parameter is audio output that reaches the ear of the listener and then goes away, rather than bouncing off side walls and ceilings to feed the reverberant field. He says that “it all comes down to pattern control,” for which he favors high-power coaxial and other point-and-shoot systems with narrower horizontal coverage.
Another primary design goal he has is localization, so that the acoustic environment of the hall, including the reinforcement coming from the loudspeakers, helps the audience focus attention on the performance rather than a particular nearby loudspeaker. He does this by utilizing digital processing to enact subtle changes in level and “frequency shading” toward the back of the hall to suggest what would happen acoustically without amplification.