What is a drywall cone

The finest acoustics in the theater

Theater, art and culture in one house - you need a lot of space - and a large budget. Usually. With the new Theater Gütersloh, however, architect Prof. Jörg Friedrich has proven that high cultural and architectural quality can be achieved without great expense. He stacked the different groups of areas of the theater building on top of each other and nested them operationally so ingeniously that his vertical theater brings the extensive overall concept of the house to full bloom in the smallest of spaces.

Plastered and finely filled reinforced concrete

The center of the new building is the large theater hall. As a reinforced concrete body plastered with Knauf MP 75 and then finely puttied, it sits in the middle of the cubic shell building and also takes up the cloakroom below the rising rows of seats in the auditorium. The foyer and a staircase are arranged on both sides of the hall. The latter serves on the one hand as an escape route and on the other hand leads to the so-called sky lobby above the theater with the adjoining roof terrace. Further staircases, galleries and a spiral staircase sculpture made of reinforced concrete, also plastered with MP 75 and finely filled, open up the different room zones within the house. In doing so, they create a lively spatial landscape within the building shell, which is completely glazed towards the city center. Their architecturally impressive openness also represents the challenge of the building: because open architecture is often associated with poor acoustic quality. But project manager architect Dipl.-Ing. Ulf Sturm, with the help of the acoustics consultants from the Kramer engineering office and the Knauf consultants, Dirk Klinker, regional market manager ceiling and Dirk Rieger, tried and tested solutions.

Acoustics and sound insulation with perforated panels

For this purpose, every single area of ​​the theater building was critically examined and treated separately. In the cloakroom under the auditorium, for example, a perforated panel ceiling made of Knauf Akustik Perforated Panels 10/23 R with a highly absorbent perforation ratio of 14.8 percent, mounted on the undersides of the gallery, prevents the holes created here and directed through the pent roof in a concentrated manner onto the opposite glass facade Sound waves lead to an unpleasant background noise.

In the sky lobby, which is open on three sides, an acoustic ceiling with Acoustic perforated panels 8/18 R with a highly absorbent percentage of holes of 15.5 percent enables familiar conversations despite the enormous size of the room.

In the square rehearsal room of the theater, however, Friedrich switched to another solution, since lighting devices are mounted on the ceiling. Dirk Klinker therefore advised the use of sound-absorbing and reflective zones on the walls, which alternate in a rhythm set by the acoustician. The panels installed for this purpose consist of plasterboard, into which perforated fields with block perforations (design BS 8/18 Q) have been punched at predetermined intervals.

Good acoustics thanks to ceiling sails and cladding

As the acoustically most significant room, the theater hall is equipped with a ceiling system made up of five curved sails. With the front side, these fields, suspended from threaded rods, reflect the sound, while the back side absorbs it with the help of mineral wool mats. In addition, the individual sails are planked with two layers of 15 and 12.5 mm Knauf Diamant panels and equipped with rock wool on the back to provide the weight of around 30 kg / m required by the acoustician2 to raise. They were completely prefabricated in the Knauf factory and delivered in the form of various individual parts that only had to be put together on the construction site using precise installation plans. At the same time as this acoustic construction task, the craftsmen from Trockenbau München, who were entrusted with the drywall work, installed additional absorbent surfaces made of perforated panels on cladding made of diamond plates on the walls of the theater. Additional absorbers on the side walls of the hall control the reflection and absorption of the sound waves. Rust-colored, in addition to the red seating, they represent targeted splashes of color in the otherwise black theater hall. This makes the lighting concept of the room all the stronger. This uses indirect light as basic lighting and a means of dividing room bodies and room zones. The headlights required for this are bundled in caissons in the ceiling sails, which are embedded in the ceiling surface and which were also prefabricated in the factory.

Daylight from light cannons in the ceiling

In the foyer, too, indirect lighting fixtures, which are integrated into a huge, curved ceiling made of plasterboard, cover the basic lighting of the room. The ceiling field that extends from the cloakroom to the window front, on the other hand, controls the acoustics of the room and guarantees a calm atmosphere. The foyer - as well as the stairwell and the sky lobby - are given radiant accents with the help of light cannons on the ceiling. In radii between 3 and 5 m, five circular truncated cones made of Knauf boards pave their way to daylight. The cones, which are partly made of prefabricated molded parts, are attached to the steel structure of the roof and each end with large glass fields so that theater-goers can always see the sky through these openings. Laterally recessed lighting fixtures give the impression that illuminating daylight falls from the cones of light into the room even at dusk - until the approaching darkness opens up the next spectacle with a heavenly view of the starry world.

From Christine Ryll

Perforated panels and ceiling sails provide soundproofing and acoustics in the Gütersloh theater

Detail and installation plans

Here you will find the laying plans for the ceiling tiles and sound sails above the auditorium as well as the detailed plans for the light cannons above the sky lobby.