Bob Coffeen stood in the center of 106 Marvin Hall pinpointing acoustical problems in the unsound classroom.
Improperly placed air-conditioning equipment on the ceiling, interior walls that caused voices to reverberate in the room and vehicles passing underneath the building's windows made it challenging to hear the architectural engineering department chairman's message.
"It's an example of what you wouldn't do if you had a choice," said Coffeen, who assisted five Kansas University students with an Acoustical Society of America publication on the subject.
Their guide on classroom acoustics has been distributed internationally. But it's not a scholarly treatment for architects and engineers. The text is targeted at educators and school planners not yet familiar with the value of quality acoustics in education facilities.
It makes clear that the problem of inferior sound in 91-year-old Marvin Hall is prevalent at schools new and old across the nation.
"Why do we ignore that?" Coffeen said. "I've been wondering that for the last 40 years."
Coffeen said recognition of this invisible obstacle has far-reaching implications for student learning.
Excessive noise and reverberation interfere with the ability of students to understand a teacher in class. In many U.S. classrooms, according to the KU guide, the "speech intelligibility" rating is 75 percent or less. That means listeners with normal hearing can understand only 75 percent of words read from a list. Imagine reading a textbook with every fourth word missing and then being tested on it.
Children are especially dependent on good acoustics, Coffeen said. With a limited vocabulary and experience, he said, young students are less capable of filling in missing words from a teacher's lecture. Faulty acoustics also add a hurdle for students with learning disabilities and students studying English as a second language.
"Being able to understand what is being said is super important," he said.
Lawrence school spaces
The quality of classroom acoustics in Lawrence public schools varies because buildings were constructed with different materials and from diverse architectural designs.
Two of the district's elementary schools, Broken Arrow and Deerfield, came under scrutiny by the KU acoustical study group.
In 1968, the district experimented by building the two "open-classroom" schools. Students are clustered in colonies. The first- and second-graders are in a single large room. The same was done with third and fourth grades and fifth and sixth grades. Originally, there were no partitions inside colonies. Kindergartners were in an enclosed classroom.
Noise made by adjacent students and teachers has been an issue, said Larry Bakerink, principal of Broken Arrow.
"It's something that teachers have to be cognizant of," he said. The open design was intended to increase flexibility in delivering the curriculum. "Yet, in many respects, open spaces are less flexible."
He said adjustable partitions have been installed to separate first- and second-graders and third- and fourth-graders.
"That's helped," Bakerink said.
Research by the KU group indicated partitions cut visual distractions but were insufficient to reduce noise. Gypsum board walls filled with fiber insulation is a better solution, the group recommended.
Finding sound answers
Coffeen, who ran an acoustical consulting firm in Kansas City for 35 years, said faulty interior spaces could be salvaged.
An example is in KU's Strong Hall, where Room 156 had been a source of complaints from people unable to understand words of a speaker standing in front of the class.
Several thousand dollars was invested in the installation of thick panels suspended from the ceiling and attached to walls. Window air conditioners were replaced with a unit that made less noise.
"At least it's not an annoying room to be in," Coffeen said.
He said school administrators should concentrate on reducing sound reverberation from walls, ceilings and floors. Cutting sound made by heating and air conditioning systems is the next step, he said. External noise should be addressed if possible.
Coffeen said schools may be forced by the federal government to pay more attention to acoustics. National standards are being developed.
"I hate that, but that may be the only way to get people to perform."