The Hottest Trends in the Design of School Acoustics
Russ Cooper | April 17, 2017
Many of the basic building blocks of exceptional acoustic design in classrooms have not changed since the 1960’s. But recent advances in building science, classroom configuration, and materials are changing the way architects and builders approach sound in the classroom.
It used to be thought that you had to use heavy masonry construction to create a sound barrier between rooms – but that’s no longer true. Today, it’s possible to achieve high levels of acoustic separation with lightweight construction like metal studs and drywall.
Today’s industry is more sensitive to issues related to school acoustics, such as improving the speech transmission index (STI) so that children are better able to hear and understand their teachers. This issue is especially crucial for children with attention deficit issues or hearing loss, as well as students trying to learn a new language.
Pressures to change the acoustic landscape are coming in the form of legislation like the Americans with Disabilities Act, which advocates equal opportunities for individuals with disabilities. It’s no longer enough to cater to the average student.
Certification programs, both voluntary and mandatory, are influencing how we think about and achieve better acoustic design in classrooms. But changes in the way classes are taught is also influencing how schools approach acoustic design. For instance, traditional teacher lectures are being replaced in some schools by what’s known as a “flipped classroom,” a movement pioneered in the 1990s by Allison King and other innovators.
In a flipped classroom, students watch prerecorded lectures at home and come to class to work on materials that used to be assigned as “homework.” The teacher is as much coach as instructor.
While the effectiveness of flipped classrooms has been debated since their inception, we are seeing more teachers today wired for sound so they are free to roam the room. Voice amplification systems are one way to overcome a noisy classroom. In many schools teachers wear a kind of harness that contains a microphone and speakers. In the not-so-distant future, sophisticated, always-on voice amplification systems will be incorporated directly into the classroom, with mics installed in the ceiling.
At times, the architectural and acoustic design communities find themselves at odds in a classic clash of form versus function. For instance, many modern buildings make extensive use of glass to increase “day lighting.” While using glass in this way can be beneficial — reducing a building’s energy footprint — it has acoustic implications. In addition, architects like to specify concrete floors and high, open ceilings to create dramatic, airy spaces. Both of these popular design decisions pose serious acoustic challenges.
Ceilings that trade acoustic tile for exposed ductwork are inherently more noisy and reverberant. To compensate for high ceilings and exposed building infrastructure, acoustic design experts sometimes recommend hanging baffles of sound-deadening material from the ceiling. These “ceiling clouds” appear as large free-form or geometric platforms suspended from wires.
To deliver exceptional acoustic performance in new school designs, aesthetic decisions — including hard surfaces, glass walls, high ceilings, and exposed ductwork — have to be identified and mitigated. And where appropriate, amplifying the teacher’s voice should be factored in.
Changing technology fuels new trends. The good news is that today’s school acoustics consultants have a wider palette of materials and techniques from which to choose.