At Macalester College, Minneapolis-based
HGA Architects and Engineers collaborated with acoustician David Kahn to renovate a
350-seat concert hall
that can be tuned for
each performance.

Credit: Paul Crosby

Goethe famously compared architecture to “frozen music,” adding that “the influence that flows upon us from architecture is like that from music.” When the design commission is a concert hall, how does one inject the aesthetic that inspired the German writer’s apt metaphor while making the space sound good for a range of ensemble sizes and musical genres?

Steven Dwyer, AIA, senior project designer at Minneapolis firm HGA Architects and Engineers, and acoustical designer David Kahn of New York–based Acoustic Dimensions tackled this challenge at Macalester College’s Mairs Concert Hall in St. Paul, Minn. Built in the 1960s, the 350-seat performance space was considered excellent—for chamber music. Over time, the campus music scene changed. Chamber orchestras now share the stage, figuratively, with jazz bands, a cappella groups, and the hard-driving beats of the popular African Music Ensemble.

To provide Mairs with the needed flexibility, HGA and Acoustic Dimensions designed an interior that can be “tuned” to accommodate all types of music, as part of a comprehensive redesign of the Janet Wallace Fine Arts Center.

The designers began by lining the interior walls of the hall’s masonry structural shell with acoustical towers that comprise three stacking acoustical shelves, each 10 feet tall. The shelves undulate and wind along the shell’s walls, enveloping both the audience and performers like a “warm wooden cocoon,” Dwyer says. The 1-inch-wide red oak pickets comprising the veneer vary by stain color, spacing, and depth—some jut out by 1 or 2 inches. Though the layout may appear random, Dwyer, a drummer since the third grade, emulated a polyrhythmic pattern similar to how members of a drum circle can follow distinct rhythms but maintain coherence through moments of coincidence.

Beyond aesthetics, the system is integral to the hall’s acoustics. The shelves cantilever progressively further from bottom to top, directing the sound down to the audience. For more intimate concerts, the lowest shelf in the stage’s back wall can roll forward in five movable partitions to ensure that the performers and their music aren’t lost in the large space.

Velour acoustical curtains, built into the towers at each shelf level and hidden by a scrim, can help dampen sound when needed. But when a soloist takes the stage, the curtains can retract and tuck behind pocket walls, exposing a 2-inch-thick honeycomb reflector panel that helps fill the hall with reverberating sound energy. “Even though the room has all this acoustical flexibility, the wall system makes it visually consistent,” Kahn says.

The acoustical towers house the acoustical curtains, wiring, accent lighting, and sprinkler piping, all concealed behind the sound-transparent scrims. Framed with tubular steel 4×4s, the stacking shelves are covered with an MDF and plywood armature, cut by local fabricators with a CNC machine. The veneer of vertical pickets, with corrugated metal mesh between spans, is primarily decorative, though it does reflect sound, particularly in areas where they are densely spaced, such as behind the stage.

In arranging the seemingly irregular wood-picket veneer on the projecting soffits, HGA was inspired by the idea of the polyrhythm, in which musicians bang out beats in different time signatures that come together as a whole due to moments of coincidence.

Credit: Paul Crosby

Once the 18-month construction phase was completed, Kahn—himself a trumpeter who often self-tests his project’s acoustics—worked with Macalester’s music directors and ensembles to tune the space. As the musicians rehearsed, the team would adjust the curtains to fine tune the absorptive and reflective qualities of the towers. Together, they developed “a series of standard settings based on different types of use,” he says. The 17-page “Adjustable Acoustics Report” provides guidance on 20 different performance scenarios, including “small vocal ensemble traditional” and “amplified music” both for small and large audiences.

Changing the tuning in between performances only takes about five minutes, Kahn says. “And at the end of the day, there’s really no right or wrong. To a certain extent, the acoustical adjustments depend on taste.” Though the manual provides recommended settings, he says, “we encourage building owners to experiment.”