Occupying an entire block in Uptown Charlotte—114,000 square feet of surprising, supple space—ImaginOn houses cutting-edge library services and collections, innovative education programs, and award-winning professional theater—all for young people and their families.

A collaborative venture of the Public Library of Charlotte & Mecklenburg County (NC) and the Children's theater of Charlotte, ImaginOn opened in October 2005 with two state-of-the-art performance halls with shop and support spaces, all under one roof. Children's theater of Charlotte runs the two theater spaces where they offer a full season of professional, adult productions for young people. The Tarradiddle Players, the Children's theater's resident touring company, offers several productions each season and also take their shows on the road. The Children's theater also offers extensive education programs, with classes for ages 3-18, and works in every grade of the local public school system.

ImaginOn—formally known as, "ImaginOn: The Joe & Joan Martin Center," after two of the city's most devoted philanthropists and activists—is the work of Holzman Moss Architecture, New York, NY (with Gantt Huberman Architects, Charlotte, NC). Acoustic consultants, JaffeHolden (www.jhacoustics.com) of Norwalk, CT, were responsible for the acoustic and audio systems design of both theaters, the 570-seat McColl and the 250-seat Wachovia.

McColl is a traditional proscenium style theater with a single balcony. Wachovia has no proscenium opening and a fixed seating riser; the front rows of seats can be removed to add a thrust stage, and moveable panels on tracks can be brought in to frame-out a stage. McColl and Wachovia were purpose-built as theatrical performance spaces. Both rooms—optimized for speech intelligibility, relatively dry, with a low reverberation time—have fixed acoustics.

Acoustic design, McColl theater
"From an acoustical stand point, design for such spaces with fixed acoustics is more straight-forward," says JaffeHolden Architectural Acoustic Design consultant, Mark Reber. "But the execution of the design still has its own flavor and surprises." The original design concept for both theaters called for Masonite peg board as the finish wall material—a touch worthy of architects, Holzman Moss, who's designs tend to incorporate materials that might commonly be used for other purposes. Pegboard is a relatively inexpensive, durable, and easily obtainable material. It was originally specified for the curved ceiling as well as the walls in McColl.

"To control reverberation, we recommended large quantities of sound absorptive material in the room," says Reber, "and pegboard is not a very absorptive material. If you put fiberglass insulation behind a perforated material, the sound goes through the holes and is absorbed by the fiberglass. Basically there's only one kind of pegboard with ¼" holes spaced on 1" centers, and a smooth, coated surface. The problem is that this material has very undesirable sound absorptive characteristics. It absorbs sound in a very narrow band of frequencies, and doesn't absorb sound in other bands."

Reber and the JaffeHolden design team identified this issue early on and, with a strong desire to realize the original intent of their long-time architectural collaborators, spent a good deal of time trying to make the design work. Compounding the problem was the concave shape of the room. A concave surface tends to distribute reflected sound unevenly and, like a dome, focus it in certain areas. Other sound-absorptive, wood, perforated products on the market that would have met the original interior design plan offered alternatives, but all proved far more expensive than common, Masonite pegboard. The pegboard idea was replaced with a fabric finish over sound absorptive fiberglass on most of the surfaces, and fabric over drywall on other areas that were intended to be sound-reflective.

"The rear of the hall, a curved surface, is mostly sound absorptive material," says Reber. The front of the hall, mostly the side walls, is sound reflective. This is helpful in reflecting sound from the stage back to the audience, supplementing the direct sound, and actually enhancing voice intelligibility and clarity."

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