When people complain about the state of public education in this country, they often focus on problems with teachers and testing. Abigail Stefaniw and Yasushi Shimizu, architects at Rensselaer Polytechnic Institute in New York, would like to add bad acoustics to the list. Reverberation and background noise often make it difficult for students to understand what the teacher is saying. Yet despite the $20 billion spent each year on construction and renovation, school systems rarely devote resources to improved acoustics.
"Most architects just don't have any education in acoustics, and certainly not for small spaces like classrooms," Stefaniw says. So she and Shimizu created computer models of three types of rooms to give builders guidance. The first was a classic shoe-box shape, the second a rectangular room with two clipped corners, similar to the spaces used for small musical performances. The third followed an original design: a trapezoidal space in which the teacher sits in one of the wide-angled corners instead of front and center. The researchers then asked a group of subjects to listen to prerecorded words modified to simulate the acoustics of each room. Stefaniw was pleasantly surprised to see that the listeners had the easiest time understanding words in the trapezoidal room. The shoe-box and music-room shapes earned distinctly lower marks. "Listeners were more tired and were guessing more of the words," she says.
Background noise only worsens the problem. Stefaniw estimates the intelligibility rating runs between 50 and 75 percent in a typical modern schoolroom with the heat or air conditioner running. "You can imagine the loss to education when children hear only two or three out of every four words," she says. Regulators carrying out the Americans with Disabilities Act (see www.access-board.gov) are currently working to develop national standards for school acoustics— something several European nations, including Germany and the United Kingdom, already have done.