Classroom acoustics.

"CAN YOU HEAR ME NOW?"

An entire marketing campaign with a slightly humorous quality was built around that phrase, but when a teacher has to stop and ask that question, it is no laughing matter. It has long been recognized that noise can hinder the academic performance of students. A 1975 study found that reading scores of students in a New York City school were lower for those whose classrooms were on the side of the school adjacent to the elevated train tracks than for those on the quieter side.

A technical report from the American Speech-Language-Hearing Association (ASHA), "Acoustics in Educational Settings," notes that, "Decades of research by audiologists, speech-language pathologists, acousticians, and others have documented the educational value of good acoustics and the detrimental effect of poor acoustics on students' auditory comprehension, learning and behavior and teachers' vocal health."

In 1998, the U.S. Access Board and the Acoustical Society of America (ASA) began work on establishing classroom acoustics standards. In March 2007, when a progress report on implementing the classroom acoustics standards was issued, the two organizations noted that levels of background noise and reverberation little noticed by adults adversely affect learning environments, especially for younger children whose listening skills are not as mature, and who therefore require optimal conditions for hearing and comprehension. Other factors that may affect listening abilities are hearing loss, speech impairments, learning disabilities or a home language that is different from the teaching language. It may be worse for children with those situations, but a noisy classroom is not an optimal learning environment for anyone.

Fifty years ago, not only was our world a quieter one, but schools were built of heavy brick or concrete block. More recent construction has been of less solid and lighter weight material. Today, when building new schools, there are a number of things that should be taken into consideration--starting with the location. Building next to a busy freeway, train tracks or an airport is obviously not recommended. But it is not just outside noise that must be considered. Having good classroom acoustics means building schools that reduce reverberation and optimize speech intelligibility.

In its booklet Classroom Acoustics: A Resource for Creating Learning Environments with Desirable Listening Conditions, ASA notes that using so-called "soft" materials such as fabric-faced glass fiber wall panels, acoustical ceiling tiles and carpeting helps to absorb the reverberation of sound. The sound you want heard in the classroom and not absorbed by noise reduction materials is the teacher's voice, and there are also ways to reflect it back into the classroom. According to ASA, these might include shaping a sound-reflecting gypsum board ceiling over the front of the room or making the center of the ceiling a hard, reflecting surface.

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ASA has suggestions for reducing noise from outside the classroom that include adding 5/8-inch-thick gypsum board on each side of the classroom wall, installing double-paned glass windows, and sealing gaps between walls and the floor and ceiling with acoustical sealant. The location of mechanical equipment should be taken into consideration during planning and building so as to minimize noise bleeding into the classrooms.

Obviously not everyone has the luxury of teaching in a brand new, acoustically ideal school, but there are still ways to reduce noise in existing classrooms. The U.S. Access Board offers some suggestions for retrofitting a noisy classroom. These include replacing existing ceiling tiles with NRC-rated acoustical tiles, or, if the ceiling is very high, adding a new suspended acoustical tile ceiling. Adding sound-absorbing panels high on walls at the sides and rear of the room also helps reduce reverberation.

Some of the U.S. Access Board's suggestions may be a bit costly, such as replacing the existing windows with thermal insulating or specially fabricated sound-reducing windows, while others are inexpensive, such as putting halved tennis balls on the legs of tables and chairs or wearing quiet shoes. Adding carpet can also help reduce the noise level in a classroom.

ASA has two publications that are available for free at http://asa.aip.org/classroom.html. Classroom Acoustics I: A Resource for Creating Learning Environments with Desirable Listening Conditions includes a general overview of problems and solutions, explanations and examples. Classroom Acoustics II: Acoustical Barriers to Learning features information about the problems experienced by teachers and students as a result of noise and reverberation in the classroom and includes more than 150 additional references on the topic.

Anne Seltz, a clinical audiologist who is an ASHA fellow and a member of the ASA group that worked on developing the classroom acoustic standards, encourages educators to become advocates for good classroom acoustics and notes that it doesn't require becoming an acoustical engineer, but at least becoming familiar with the basic concepts of acoustics and promoting basic noise control. In her article, "Let the Word be Heard: Be an Advocate for Good Classroom Acoustics," which can be found on the ASHA Web site, she offers suggestions such as help your school find an expert on acoustics; obtain a sound level meter that can measure down to 35 dBA; and form an advocacy group of staff, students and parents who are affected by the problem.

According to Seltz, "The modest cost of providing good acoustics is more than paid back by a better educated society."

While that may be true, tough economic times may make it harder to implement the needed changes, and classroom acoustics may not be a very high priority at most schools. And yet we know that children deserve the most optimal environment for learning, and that includes a classroom where they can clearly hear the teacher's voice and not the HVACR equipment clanging off and on, the film being shown in the classroom next door or the gym class going on outside. They should be able to concentrate fully on their education, and the answer to the question, "Can you hear me now?" should be, "Yes, loud and clear!"

Learn More

To find out more about creating good acoustics in the classroom, here are some Web sites to visit.

Acoustical Society of America

http://asa.aip.org

Alexander Graham Bell Association for the Deaf and Hard of Hearing

www.agbell.org

American Speech-Language-Hearing Association

www.asha.org

Classroom Acoustics

www.classroomacoustics.com

National Clearinghouse for Educational Facilities

www.edfacilities.org/rl/acoustics.cfm

U.S. Access Board

www.access-board.gov

Quiet Classrooms

www.quietclassrooms.org/index.htm

Susan Reese is a Techniques contributing writer. She can be contacted at susen@printmanagementinccom.