How colleges are upgrading classroom acoustics
College classrooms of yore were often fortresses reinforced with concrete floors and walls. Listening to a lecture in such hard-surfaced rooms was like trying to decipher sound in an echo chamber.
After years of complaints from students and faculty, many colleges and universities have begun upgrading classrooms and lecture halls by installing ceiling baffles, fabric-covered wall panels and carpeting over concrete floors to improve acoustics.
At the same time, these retrofits are accommodating new teaching formats such as active learning, in which groups of students collaborate on projects and need to hear one another.
Enhancing acoustics and reducing background noise from heating and ventilation systems can cost up to tens of thousands of dollars for larger instructional spaces. Yet campus leaders are increasingly recognizing the critical role of acoustic design in creating an environment where speech is intelligible.
“Acoustic design can take a room that’s pretty much unusable to one that’s in high demand for the university,” says Greg Coudriet, principal consultant in the acoustics department at The Sextant Group, a Pittsburgh-based AV-focused firm.
Colleges can follow four rules for improving acoustics and minimizing ambient noise in all types of instructional spaces.
1. Don’t let acoustic problems in older classrooms linger.
At the Community College of Allegheny County in Pittsburgh, students attending classes in any of the library’s three lecture halls had the same criticism. They couldn’t hear their professor. Those classrooms, constructed in the early 1970s, had concrete ceilings and floors, brick walls, and hard, plastic seating.
Campus officials decided to fix the sound issues three years ago by hiring acoustical consultants from The Sextant Group to help reduce the reverberation in two of the rooms, each seating about 70 students.
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After wall panels, carpeting and soft-surfaced seats were added, students could hear a clear difference in the rooms, says J.B. Messer, chief facilities officer at the college.
Another attempted solution—a microphone system—made the acoustics worse, he adds. “It created more of an echo and just exacerbated the problem.”
Acoustical wall panels also reduced reverberation in a 495-seat auditorium used for lecture classes at Marquette University in Milwaukee. Students complained that they couldn’t hear professors in the auditorium, which was originally designed as a performing arts space.
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After hiring acoustical consultants from Orfield Laboratories of Minneapolis, the university installed a series of fabric-covered panels in strategic locations along the walls in 2015. Other renovations that improved sound included upgrading the microphone system and adding more speakers on the stage.
Although the auditorium still hosts concerts, the change in acoustics was more noticeable when it was used as a lecture hall. Students have reported being able to hear better now, says Kathleen Kugi-Tom, project manager for facilities planning and management at the university.
2. Recognize that smart classrooms have different acoustic needs.
When active learning classrooms began cropping up on college campuses in the 1990s, they not only changed teaching style but also the acoustic dynamics. As instructors moved away from lecturing, the need to hear students collaborating throughout the classroom became more critical.
“When several groups of students are talking to each other, the acoustical environment is more like a restaurant,” says Coudriet of The Sextant Group. “You need to have speech intelligibility in all directions because there’s no real front of the room.”
Ensuring all students are heard requires placing acoustical enhancements throughout the space.
That was the strategy used by a team at Columbia University this year in a project involving the renovation of a former library—located on the fourth floor of a century-old chemistry building—into an active learning classroom.
The space’s 120 chairs can rotate 180 degrees, allowing students to swivel around and work at a common table with the row next to them. “We knew there would be a lot of sound bouncing off the wall,” says William Wong, an architect and associate at Spacesmith of New York, which worked with an acoustical consultant to design the space.
In addition to installing floor carpeting and acoustical paneling across all the walls, the firm recommended the ceiling be covered with acoustical baffles—rectangular beams hung on their side that can absorb sound and reduce echoes.
The university also installed about 15 speakers to amplify sound throughout the room and replaced aging steam radiators with new heating systems, Wong says.
3. Ensure acoustics is considered from the beginning.
Because acoustics dictate many key elements of an academic building—such as its shape or materials—the type of sound system that will be used must be a key early consideration.
When the University of Massachusetts Boston built its newest academic building in 2016, architects designed a 500-seat lecture hall in an egg shape to allow the speaker’s voice to fill the space.
“Acoustics affects how you’re laying out the shape of the building, which plays a critical role in how sound travels,” says Andrew Weiss, the university’s campus planner.
A shaft next to a café in the $130 million building filters noise away from an adjacent classroom. An additional floor beneath a dance studio and a dropped Sheetrock ceiling in a classroom below prevent noise from disturbing the instructor and students.
Hiring an acoustical consultant who can recommend the most up-to-date solutions is important when beginning projects, facilities administrators say.
“It’s no different than hiring an electrical or structural engineer,” says Robert LaVigne, associate vice president for facilities management at Nichols College in Massachusetts. If the architect designing the project can recommend acoustic best practices, an acoustical consultant may not be needed, he adds.
When the college built an academic building with five new classrooms in 2016, officials contracted with the consulting firm Cavanaugh Tocci to provide technical expertise on the acoustics. The consultants advised administrators to install acoustical ceiling tiles and wall panels with high NRC (noise reduction coefficient) ratings to soak up sound.
4. Be proactive by assessing existing learning spaces.
Instead of waiting until acoustic problems arise, Rochester Institute of Technology in New York is surveying all 180 registered classrooms to determine whether the rooms have ambient noise or excessive reverberation.
RIT is conducting the assessment as part of the Learning Space Rating System (UBmag.me/lsrs) developed by Educause, which measures how well a classroom’s design promotes active learning.
In 2017, administrators reviewed all the classrooms on campus and now plan to conduct a more detailed study to determine if the rooms need audio amplification and reductions in ambient noise (often from heating systems). The noise levels will be measured by sound meters placed in the classrooms.
“If you can’t measure it, you can’t prove anything will improve the situation,” says John Moore, RIT’s assistant vice president for facilities management services. “Surveying the existing conditions is going to give us a path and a way forward to solutions that will make our spaces better.”
Facilities administrators at other institutions, such as UMass Boston, audit classrooms annually to determine if there are acoustic problems.
Since many of its academic buildings—built in 1974—have polished concrete floors, the university each summer uses funding from its operating budget to install carpet tiles and sound-absorbing paneling on the walls and ceilings in classrooms that have acoustic issues.
Reviewing sound systems also means that acoustical ceiling tiles, which have been a standard for at least 40 years, often need to be replaced. “Changing up those ceiling tiles, which we periodically have to do because they get stained or cracked, really makes a difference,” says LaVigne of Nichols College.
“We all don’t have the ability to rip the walls down and put in acoustical insulation. We have to work with our resources.”
Sherrie Negrea is an Ithaca, New York-based writer and a frequent contributor to UB.