Noises carry

July 1, 2014
Flooring as one solution to the multifaceted problem of classroom acoustics.

Despite the influx of technology-based teaching in classrooms, actual teachers remain critical to learning. However, teachers’ effectiveness depends on their students’ ability to hear and understand them. Often, classroom acoustics influence this ability.

Various sound-related factors compete with the teacher’s voice. The first is reverberation, a series of quickly repeated sounds that bounce off hard, smooth surfaces, like walls, nonporous floor coverings and furniture, until they are absorbed or eventually dissipate. Echoes, too, can be a problem, especially in large, open classrooms, auditoriums, gymnasiums and multipurpose spaces.

Teachers also must contend with competing exterior noise from weather, traffic, airplanes, trains, and construction, often even when windows are closed. Inside, hallway noise, foot traffic, doors opening and closing, adjacent classrooms and open floor plans contribute to distracting noises.

Within the classroom HVAC systems, computers and voices add to the clamor. According to a number of studies, the typical noise level of classrooms is 60 dBA, which exceeds the conversational voice level of many teachers. At times, the noise level of an occupied classroom can reach 75-85 dBA, making it difficult for a teacher to be heard.

This noise, coupled with reverberation, can negatively impact student performance, as indicated in a study conducted by Finitzo-Hieber & Tillman (1978). Students tested in an audiometric booth with negligible noise and reverberation achieved mean speech recognition scores of 95 percent, while those in a classroom setting reported scores of 30 to 83 percent.

And while good acoustics are important to all students, they are especially important to younger children, whose speech, language and listening skills are not yet fully developed and who demonstrate difficulty separating sounds from background noise. Students with learning disabilities and hearing impairments also gain special advantage from good acoustics.

Teachers, too, appreciate the benefits of good acoustics. It is easier for them to provide instruction, and they are not forced to speak louder, which can be physically stressful, even causing fatigue and vocal cord damage over time. A noisy environment can also challenge students who are trying to concentrate on exams or hear instructions.

So what’s a school to do? One obvious solution is to move students closer to the teacher. The other more long-term, sustainable solution is to design new schools and renovations with acoustics in mind, carefully combining reflective, absorptive and diffusive surfaces. To help, the American National Standards Institute (ANSI) publishes standards in conjunction with the Acoustical Society of America, with the goal of improving the intelligibility of speech in the classroom. According to the standards, a teacher’s voice needs to be 15 dB higher than background noise. The classroom target is 35 dB of background noise and a reverberation time of 0.6 seconds or less.

To meet these standards, schools can select materials that impact acoustics – things like ceiling tiles, window treatments, chair casters, door closures, upholstered furniture and flooring. Some rubber floor coverings have been shown to attenuate 70 percent of unwanted noise and absorb as much as 17 decibels of sound. The distractions students and teachers face range from other students in the classroom to the technology designed to help them. But whatever the distraction, the common denominator is often noise. Addressing noise with rubber flooring and other sound-absorbing materials goes a long way toward improving acoustics, providing teachers with opportunities to better communicate with their students and giving students opportunities to better retain information and concentrate on their studies.

Tasha Hughes is a public relations and marketing specialist for nora systems, Inc., an international rubber flooring manufacturer. She can be reached at [email protected].

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