Teachers use their voices all day. When noise leaks in from outside the classroom, teachers must raise their voices to be heard, and their voices become strained. The constant strain on vocal cords can lead to greater teacher absenteeism and shortened teacher careers. Moreover, background noise significantly affects student attention, behavior, and achievement. Soundproofing is not an option for most classrooms, but technologies, techniques, and guidelines can ensure that teachers and students make the most of their sometimes imperfect learning environments.
Noise Affects Teachers
Teachers who work in schools with noisy classrooms must constantly raise their vocal volume in response to varying levels of background noise. Noisy ventilation systems that cycle on and off, poor insulation between classrooms that allows sound leakage, hard surfaces that reflect student noises, and such outside noise sources as traffic and airplanes cause teachers to strain their voices.
On average, teachers talk for 6.3 hours during a school day (Siebert, 1999). Eighty percent of teachers in one study claimed that they had experienced vocal fatigue, and more than 20 percent of teachers report that voice problems caused them to miss from one day to one week during the school year (Allen, 1995; Gotaas & Starr, 1993). In addition to concerns about teacher health, the financial implications of hiring substitute teachers for teachers who are forced to miss work is considerable.
Teachers constitute more than 20 percent of the voice-clinic load, or five times the number expected by their prevalence in the work force (Titze, Lemke, & Montequin, 1996). One study of more than 1,000 teachers found that almost 21 percent had a pathological voice condition (Urrutikoetzea, Ispizua, & Matellanes, 1995). Occupational medicine specialists are increasingly recognizing these voice problems as a work-related risk. More than 4 percent of teachers considered changing their current job because of their voice problems. The higher frequency of vocal-strain symptoms experienced by teachers (67 percent) compared with nonteachers (33 percent), regardless of age, suggests that teachers are at high risk for vocal abuse (Smith, Gray, Dove, Kirchner, & Heras, 1997).
Noise Affects Teaching and Learning
Teachers aren't the only ones affected by noise. Studies have found significant differences in both performance and behavior between students working in quiet conditions and students working in noisy conditions.
Young learners typically have short attention spans and high distractibility, which makes them ineffective at sorting speech from noise. Figure-ground discrimination is the skill that allows listeners to pay attention to a specific sound—such as a teacher's voice—or to ignore or "listen through" distracting background noise. These skills do not mature until approximately age 13 (Crandell, 1995). Young children require speech to be much louder before they can recognize words as accurately as adults can (Elliott, 1982). Also, excessive reverberation—such as an echo—smears the acoustic properties of speech because the noise masks word endings, high pitch speech sounds, and words spoken by peers. Further, experts have recognized for at least 30 years that the loudness of background noise in a typical classroom is almost as loud as the teacher's voice (Sanders, 1965).
Ironically, the classrooms with the loudest noise interference have been the ones with active young children who, because of the development of their auditory systems, have the greatest difficulty comprehending speech in the presence of background noise. As these children learn to read, they need to hear minor differences between words, which can easily be lost in a sea of noise. The task is more difficult for students with minimal or fluctuating hearing loss.
Noise Affects Behavior
Attention span, focused listening, and appropriate classroom behavior are also compromised by excessive noise in classrooms. When a ventilation system automatically turns on, for example, the teacher must raise his or her voice to overcome the competing noise. Students must increase their efforts to focus on what the teacher is saying. Children's restlessness, activity levels, and self-generated noise also increase. The overall stress level within the classroom increases when the teacher's voice rises to a higher level. Verbal instruction breaks down and becomes ineffective. Teachers must repeat instruction given to a group to many individual students before all can understand and follow directions. Group discussion becomes ineffective because fewer students can hear other students' voices well enough to understand what they are saying.
Noise Affects Special Populations
Although noise affects all teachers and students, the problem is compounded for those students with hearing problems. Research indicates that 30 to 43 percent of elementary students have minimal degrees of permanent or fluctuating hearing impairment that could adversely influence listening and learning (Flexer, 1989; Ray, 1992). These same studies found that 72 percent of students enrolled in special education had some degree of a hearing deficit. On the basis of this information, it is not a surprise that many students identified with attention or learning disabilities have significant histories of hearing loss (Reichman & Healey, 1993).
A study revealed that of children who had characteristics of giftedness but did not score within the gifted range on intellectual tests, 75 percent had significant histories of fluctuating hearing loss (Silverman, Chitwood, & Waters, 1986). Even minimal or fluctuating hearing problems can have a subtle, deleterious effect on young learners.
In districts where the effects of poor classroom acoustics on listening and learning are not recognized, too often students with hearing disabilities need elaborate and expensive special education programs. The district hires greater numbers of learning specialists and purchases hearing technology equipment so that these students can have access to classroom instruction or be taught in small groups what they could have been learning in the regular classroom if the acoustic conditions had been better.
Sound-Field Amplification
Despite the range and complexity of problems associated with noisy classrooms, some solutions exist. One solution is to provide teachers with a sound-field amplification system. Teachers wear small, wireless microphones that transmit sound to a receiver system attached to speakers around the classroom.
When the teacher's voice is comfortably louder than the background noise, all students in the classroom benefit, including children with mild hearing problems. Students in amplified classrooms learn at a faster rate, to a higher degree, and with less repetition of information than if the teacher's voice is not comfortably louder than background noise. One local education agency that implemented sound-field classroom amplification in 60 classrooms over five years found nearly a 40 percent reduction in the number of students placed in programs for learning disabilities (Flexer, 1989).
Another obvious benefit of a sound-field amplification system is that teachers do not have to raise their voices above a conversational level to be heard clearly throughout the classroom. Just as an overhead projector helps students focus on the teacher's written presentation, an amplification system helps all students focus on verbal instruction.
Teachers with diagnosed vocal pathology have been successful in obtaining sound-field systems in their classrooms as an accommodation required by the Americans with Disabilities Act. The Act requires reasonable accommodation for persons with disabilities to perform the essential functions of their jobs. In the case of a teacher with medically significant voice problems, a reasonable accommodation in the workplace might include the school district providing an amplification device for the teacher to use for verbal instruction in the classroom. The U.S. Justice Department's interpretation of the Americans with Disabilities Act states that the public entity must provide an opportunity for individuals with disabilities to request auxiliary aids and services of their choice. The public institution shall honor the choice unless it can demonstrate that another effective means of communication exists or that the use of the means chosen would not be required under the regulation. One school obtained sound-field systems for all classrooms after a remodeling project replaced a relatively quiet ventilation system with a new, inexpensive, but louder, system.
Classroom Acoustics
Although amplification technology in the classroom can help teachers and students, the effective use of this technology assumes that a classroom will have acceptable sound reverberation and reasonable levels of background noise. Amplification technology will not solve all of the listening problems caused by a loud ventilation system or leakage of sound from other classrooms caused by poor acoustics.
The U.S. Architectural and Transportation Barriers Compliance Board, an independent federal agency devoted to improving accessibility for people with disabilities, supports the development of a standard for classroom acoustical design by the American National Standards Institute. The Institute has developed a standards document to define acoustics criteria for new and remodeled educational facilities. These acoustical guidelines, the first federal document to specify acoustics criteria, can guide school districts in providing an appropriate educational environment for students with auditory impairments. If the Board responds favorably to the Institute's petition, the guidelines will be enforceable under the American with Disabilities Act. (For more information, see www.access-board.gov/publications/acoustic.htm.) These guidelines are especially important now because one-third of all schools in the United States need extensive repair or replacement and 60 percent need replacement or extensive repair of at least one major building feature (General Accounting Office, 1995).
A 1995 General Accounting Office report documented a need for acoustics for noise control and called acoustics the top environmental issue that needed to be addressed in schools. Despite this report, most school administrators fail to recognize the harmful effects of inadequate classroom acoustics. Including adequate acoustics in the building plan typically accounts for less than 1 percent of the total budget—often less than the landscaping. The instructional value of bushes is debatable, but research shows that appropriate acoustics can help children hear and learn.
For many new and remodeled schools, wiring for amplification systems in classrooms would be an inexpensive part of a school's technology plan. Compared to other technologies used in schools, sound-field amplification has a high instructional benefit to students and teachers and is user-friendly and inexpensive. The more experience with sound-field amplification that teachers have, the more they praise it because their students pay attention for longer periods, are less distracted, and have less need for individual reinstruction. Given an appropriate acoustic environment, sound-field amplification allows every student to hear as well as if he or she were in the front row and allows teachers to instruct without damaging their voices.
