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Researching Teacher Benefits / Preference

Reduced Vocal Fatigue

When background noise is competing for a teacher’s attention, the teacher automatically raises his or her voice. As was stated earlier, a conversational voice is around 65 decibels and the average background noise is approximately 50 decibels. This would provide an SNR of +15 dBA, the necessary signal to noise ratio for speech intelligibility of the normal hearing English speaking child. But, that assumes that the child is within conversational distance from the teacher, 2-3 feet; which we know is not possible for the majority of the students in the class. Therefore, with a background noise level of 50 decibels, the teacher would need to raise her voice up to 83 decibels so that children in the back row (approximately 8 feet from the teacher) can achieve a SNR of +15 dBAs.

Now realistically, teachers are not monitoring the SNR in the classroom throughout the day. Most teachers are not even aware of the required SNR for children, nor are they aware of the actual noise level in the classroom, and we know from ASHA and other research that the SNR in the back of the room is not at the minimum level acceptable for children. But teachers realize, on some level, that they need to project their voices above the noise level in the room, in an effort to have all the children hear them.

There is always the teacher, resistant to voice enhancement technology, who claims that all the children can hear her because she has such a loud pervasive voice. Some teachers even boast about their “vocal” abilities. But those teachers are unaware that sounds have different frequencies and those frequencies have varying degrees of audibility depending on whether they are high or low. For example, consonants are carried by the weak high frequencies, while vowels are carried by the stronger low frequencies. Ninety percent of the energy of speech is carried by the low frequencies, yet only 10% of the intelligibility resides in the low frequencies. Therefore, the louder the teacher talks the less intelligible becomes the sound, because loud voices power the vowels, but obscure the consonants (the softest components of language). It is the consonants that are at the beginning and ending of words and infer meaning, so parts of the word may become more audible, but the word as a whole becomes less intelligible. Loud voices as opposed to a soft nurturing voice are less conducive to learning and present health issues for the speaker. This constant excessive loud talking (even yelling at times), wears on the teacher’s voice and the teacher’s physical stamina, causing pain, fatigue, throat infections, laryngitis and other voice related problems.

How does this impact the teacher and how does it impact the students? The majority of verbal interaction in the classroom consists of teachers talking to students. This results in teachers talking on average 6.3 hours per day, which accounts for the fact that while teachers make up only about 4 percent of the working population, they compose about 20 percent of the patient population in voice treatment centers (Titze et al., 1997). It simply is unnatural to speak this long and this loudly for the majority of the working day. The magnitude of teachers’ voice problems and subsequent societal effects may be best illustrated by recently published epidemiological studies reporting that teachers are 32 times more likely to be plagued with voice problems than any other voice dependent occupation (Smith et al., 1998). Subsequently, teachers are often absent from work for a vocal related issue. According to the National Center for Educational Statistics, teachers miss an average of 2 days per year due to vocal fatigue. In fact, in a study comparing teaches to non-teachers, about 20 percent of teachers (compared to only 4% of non-teachers) said that they have missed work due to a voice problem, and 16% had actually cut-back on teaching activities as a result of the chronic adverse impact on their voice (Smith et al., 1998).

Teachers, often unaware of the significance of this “occupational hazard”, don’t realize what a profound deleterious affect this excessive loud talking has not only on their own health, but on education and society in general. When voice related issues become serious enough that a teacher misses school, the children and society pay for it. Even the best prepared substitute teachers are no match for the professional experience and daily rapport that teachers have with their students. The curriculum is interrupted. Students view a day with a substitute as a “vacation” day, and valuable time is wasted. There is a significant financial cost as well. While each substitute is paid a nominal fee, on average $75 to $100 per day, the summation of substitute pay for a school or school district becomes financially oppressive. The voice problems of teachers cost the U.S. economy more than $2.5 billion annually (Verdonlini and Ramig, 2001); money that could be better spent on equipment which conserves the teacher’s voice AND is more effective at providing acoustic accessibility to the students.

A study in Dubuque, Iowa confirms this theory where 60% of the teachers who had ever used a sound enhancement system estimated that they took an average of .97 sick days per year due to a vocal related illness. However, the 40% who used a sound enhancement system averaged only .34 days per year per teacher for a vocal related illness (Allen 1995).ⁱ Therefore, this data supports the idea that the installation of sound enhancement equipment not only prevents vocal abnormalities and conserves the teachers’ health, but also has a tremendous financial cost-savings benefit as well. At $100 per day for substitute pay, a sound enhancement system (estimated at a cost of $1500) can pay for itself by preventing 15 days of substitute pay for the teacher in that classroom.

If schools are serious about achieving federally mandated student achievement goals and school accountability standards, they must prioritize the vocal needs of their teachers to realize educational improvement and school reform. Quite simply, vocal communication is the primary occupational tool of the teacher who is most directly involved in the student learning process. When the teacher’s voice is hampered by pain, horseness, or low volume, students’ learning is placed at risk and interrupted, and causes a profound financial burden to society as well.

Relief from vocal strain is the most obvious benefit to teachers from use of sound enhancement systems. However, integrating this technology in the classroom produces changes in the temperament of the students, which provides a secondary benefit to teachers.

Improved Classroom Management

A Brigham Young University (BYU) study found that the problem with student learning today could be attributed more to the learning environment than to the teacher, the curriculum, textbooks, or educational software. This study supported an earlier Cornell University study that found if students can’t focus on the teacher’s spoken word, they lose not only the desire, but also the ability to learn (Evans 2001). Consequently, introducing a sound enhancement system into the classroom, changes the learning environment for the student and the teaching environment for the educator.

When the school facilities do not support auditory learning, boredom and fatigue are likely to result, fostering an environment of inappropriate and inattentive behavior; possibly contributing to the excessive diagnosis of ADD in America. “Up to 19% of school age children have behavioral problems, with up to one half of them displaying attention or hyperactivity problems.” ⁱⁱ

Modifying the acoustic environment with a sound enhancement system, allows the students to easily hear and understand their teacher, conserving energy that would otherwise be spent on processing sounds and trying to decipher their meaning. More energy to the student means less “tuning-out” from exhaustion and fatigue. The student is able to focus on the lesson or the task and becomes an active participant engaged in discussion, activities, and learning. This in-turn changes the total dynamics of the classroom and reduces the burden of disciplinarian for the teacher. Teachers are allowed more time to teach due to the reduction in time needed to “manage” the classroom and get students back on task.

The findings from a New Zealand study support this theory. An 8 week observation of sound enhanced classrooms, alternating 2 weeks on and 2 weeks off using the system, found that with the sound enhancement system on, on-task behavior ranged from being 14% less on task to 50% more on task, with a mean of 18% more on-task time than when the system was off. Findings were similar for children with normal hearing and those with a hearing loss (Allcock, 1999).

Children’s desire to learn is returned when the frustration of learning is eased; frustration that previously manifests itself in many forms including disciplinary problems. Sound enhancement technology improves student behavior; a theory supported by numerous research studies and by the principal at Florida’s State Demonstration Middle School in Orange County, Florida. Principal, Dr. Kate Clark noted a 40% decline in discipline incidents over a one year period after the classrooms were sound enhanced. It makes sense that if a student can focus their attention on learning, they become more interested in learning, more engaged in the classroom, and less apt to become distracted or unruly.

Teachers who use sound enhancement equipment report that students are more attentive, less distractible, and require fewer direction repetitions (Allen & Patton, 1990).ⁱⁱⁱ This all lends itself to a calmer classroom environment more conducive for learning and more apt to retain good teachers that will not “burn-out” too quickly.

Greater Mobility

Reduced teacher vocal strain is not the only benefit of verbal instruction. Sound enhancement systems allow the teacher greater mobility in the classroom, because the teacher no longer has to be concerned about acoustical barriers and interrupted speech signals. With speakers strategically placed throughout the classroom, every child is within a short distance of the teacher’s voice, ensuring that all students have a signal to noise ratio of +15 dBA. This means that teachers can talk while writing on the chalk boards and not be concerned about children who previously needed preferential seating for a hearing problem or learning disorder. In essence, all children in the class have “preferential seating” without the stigma or formality of qualifying for it. This takes a tremendous burden off the teacher, so that she can concentrate on what she wants to say, rather than where she needs to say it.

Summary table of sound enhancement efficacy studies demonstrating teacher preferences and benefits

Table data taken directly from Sound Field Amplification: Applications to Speech Perception and Classroom Acoustics (Second Edition) by Carl C. Crandell, Joseph J. Smaldino, and Carol Flexer.