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System improves sound dispersal in a university conference hall

March 1st, 2009 / By: / Feature

Improving the acoustics of the Steven Holl-designed architecture building at the University of Minnesota.

Even some of the best-laid design schemes of the most notable architects can go astray. Take the case of a modestly scaled, second floor conference room in Rapson Hall, the home of the University of Minnesota’s College of Design, designed by Steven Holl in 2002. The issue was noise. The austere minimalist room, measuring approximately 6m by 12m, is a high-traffic site for meetings, small lectures, formal and informal pin-ups and model displays. Its acoustically reflective concrete floor and ceiling and sheet rock walls proved to be a reverberation headache and its users soon knew the problem needed to be fixed.

The answer? Marc Swackhamer’s inventive Disperse, a system of reticulated felt panels mounted on Homasote® (recycled pressed paper mixed with a glue and water) and installed like a liner of a cooler on three of the room’s four walls. Although the project required more than two years to conceive, execute and install, it is a success for multiple reasons.

Aesthetically, its gunmetal grey, industrial grade recycled felt is in sync with the industrial feel of the room. Functionally, it not only absorbs sound but is an excellent surface for pinups. Ingeniously, each rectangular panel, through a hinge system, can be pulled out 90 degrees from the wall like a shelf for temporary model display or presentation materials. Perhaps most importantly, Disperse became an innovative, trial and error labor of love for Swackhamer, an assistant professor in the College of Design, numerous graduate students and wood shop director Kevin Groenke, as they designed prototype after prototype after prototype out of paper — more than 20 in all.

“Working with the students was great,” remarks Swackhamer. “I keep impressing upon them the value of the reiterative process. To get the best possible solution, you often go through a lot of failed attempts.”

Each of the dozens of rectangular felt panels was laser cut with a series of openings or holes, in one of 13 different patterns, to absorb sound to various degrees. The panels behind where a speaker would stand have the most number of holes, making them more sound reverberate. The panels at the far end of the room are cut with the least amount of holes, making them more sound absorptive. “It is not a stagnate pattern of forms, of holes,” explains Swackhamer. “There is movement throughout the piece.” The actual geometry of the holes was inspired by the shape of the metal clips used by students to hang flat work for pin-ups. Laid out in a running grid pattern, Disperse brings to mind nothing so much as a wooly Sol LeWitt wall mural.

The project presented numerous challenges. An acoustician was brought in to help determine the overall acoustical issues. Then there was the problem of how to attach the felt to the Homasote. Threading fingers of felt through the Homasote and glue was the answer. Then there was the problem of how to design the felt to serve as both a hinge and bracket for the shelves. The solution? A sophisticated design that folds up like an envelope. And then there was the issue of how to clasp the panels to the wall: small black screws. Initially, Swackhamer tried to cut the varying-sized holes in the felt with a water jet but there was not enough precision to the process. Using a laser cutter and CNC router was the answer. To accomplish the cutting, Swackhamer worked with Ameristar Laser Co. and Industrial Art and Design, both Minneapolis companies.

“Industrial felt was the fabric of choice for this project,” explains Swackhamer. “It is flexible, dense, absorbs sound and was strong enough for the hinges and brackets. It also comes in different thicknesses and colors. It was a recycled material and it can be recycled. It was the perfect choice.”

Swackhamer has taught at the University of Minnesota’s College of Design since 2004. The project began in 2005 and was installed in 2007.

Mason Riddle, a contributing editor to Fabric Architecture, writes frequently about design, art and architecture.

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