Acoustical Society of America
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Revisiting Speech Interference by Noise in Classrooms and Considering Some Possible Solutions

Michel Picard (514) 343-7617 - picardmi@MAGELLAN.UMontreal.CA
Ecole d'orthophonie et d'audiologie
UniversitČ de MontrČal
C.P. 6128, succ. Centre-ville
MontrČal, Qc, H3C 3J7

John S. Bradley (613) 993-9747 - John.Bradley@nrc.ca
Institute for Research in Construction
National Research Council
Ottawa, ON, K1A 0R6

Popular Version of Paper 2pAAa3
Presented Tuesday afternoon, June 17, 1997
133rd ASA Meeting
State College, PA
Embargoed until June 17, 1997

Today's classrooms are extremely noisy environments. In fact, they are so noisy that most students from kindergarten to high school are likely to experience significant problems hearing the voice of a teacher. A review of current data on noise and reverberation in these facilities indicates that poor acoustics is the prevailing condition rather than the exception. In particular, environmental noise levels during regular school activities are approximately 4 to 38 decibels above values currently agreed upon for optimal speech recognition by normal-hearing children and the situation would be no different for hearing-impaired children taught in special classrooms. For instance, in representative conditions, normal-hearing first-grade students would recognize only 66% or so of the words being spoken by the teacher This is a quite alarming situation in addition to vocal fatigue experienced by teachers as a result of sustained efforts to rise their voice well above the din.

Intruding noise from the outside and from adjacent classrooms as well as noise generated (or transmitted) by heating and ventilation equipment are part of the problem. Internal noise generated by children represents a significant contribution to overall environmental noise levels with younger students being the noisiest groups. Of course, this results partly from their limited attention spans and partly from the fact that this is typically the time in which they learn classroom discipline. Moreover, noise levels in the classroom are exacerbated by reverberation properties of the room. With greater reverberation levels, there is a greater buildup of noise which then propagates more uniformly throughout the room.

Architectural and engineering solutions will be of great help in reducing external noise sources penetrating either from the outside or from adjacent classrooms or corridors. Some example measures include improving the design of heating/ventilation systems, carefully installing these systems, adding acoustical insulation to partitions, double-glazing windows, padding interior walls and surfaces with absorptive materials. Not only will these solutions significantly reduce noise levels in classrooms but they also are quite simple and straightforward techniques. As such, they are not prohibitively expensive, certainly not to the point of deterring school administrators from taking action. Therefore, these solutions should be the first approach considered for improvements. In addition to easing the burden for teachers, they provide benefits for all users of classrooms: normal-hearing and hearing-impaired children, non-native speakers of English. However, architectural and engineering solutions will be more difficult to implement in existing school facilities and modifying open-air classrooms will be especially difficult. They will also have limited benefits in controlling noise generated by children.

Identifying more ecologically-minded approaches like increasing the voice of the teacher well above noise levels is a difficult task too. For example, introducing loudspeakers in the classroom may very well disrupt adjacent classroom activities. Similarly, training teachers to become louder or more intelligible may mean that their voice can possibly be heard in adjacent rooms. Weighed against their potential side effects, the modest benefits these measures would bring are clearly not large enough to be considered a general solution to the noise problem in classrooms.

Thus, there appears to be no simple solution to noisy classrooms. Exploring innovative solutions like capitalizing on visual speech cues and facial expressions may have to be considered. Quite obviously, benefits of audiovisual speechreading can reasonably be expected from teachers specifically trained to be highly visible speakers. Similarly, implementing efficient communication strategies to ensure that what is being taught is at least correctly heard by children may also provide useful.

With the hearing-impaired, amplifying the voices of teachers and providing the assistance of interpreters are basic services to be offered right at the beginning of the school curriculum. Employing notetakers would also be required whenever children start to acquire general knowledge beyond basic reading, writing and mathematics. Clearly, managing the noise problem in the classroom calls for the collective and coherent effort of architects, engineers, educators and rehabilitative audiologists to free children from one of the most pervasive but insidious limitations to academic achievement in the school population. For that reason, it currently represents a major challenge in education.


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