Classroom Amplification

• By Thomas G. Dolan
• 08/01/09

Claudia Anderson had two sons who were profoundly deaf. She knew in her heart that they were perfectly intelligent. But what could she do to help them out? What resources could she turn to? Back in the mid-1970s, there wasn’t much. She was on her own. What she did was turn her personal tragedy into a triumph in a way that has helped not only her children, but countless others.

At a fundraiser in 1976, Anderson noted a cameraman was in one location, while an announcer was in a totally different location, but the words and images appeared to be happening simultaneously in one place. Why, the wireless microphone.
The next day, Anderson purchased one of these devices, on the premise that if you can get the announcer's voice into the camera, why couldn't you get the teacher's voice into the ears of the students?

This led to her founding of a company that manufactures devices for this purpose — Audio Enhancement. As explained by the company’s senior vice president, Tom Dobson, the source for this information on Anderson, though her initial intent was to help the auditory needs of students with hearing disabilities, she soon realized that enhanced amplification could be a learning boon to all students. For instance, if a teacher spoke into a microphone on her desk, and her voice went into a speaker on an impaired student's desk, the learning capabilities of the four or five students sitting around that student also improved significantly.

Although Anderson was a pioneer in addressing this problem, it soon became clear that poor acoustics in schools was widespread. In 1981, the government published the Multiple Area Resource Room Study (MARRS). Here, again, the initial focus was students at special risk, although this group comprised 20 percent of the school population. These included children with any hearing loss, whether unilateral, bilateral, high frequency, minimal or fluctuating. But the study also focused on children younger than age 13, those with articulation disorders, language learning problems, learning disabilities, non-native English speakers, those with a history of otitis media (infection of the middle ear) and those with auditory processing disorders.

The study found that high noise levels which led to acoustical problems included excessively loud heating-ventilation-air conditioning units (HVAC), plus lights, AV and electronic equipment, pencil sharpeners, aquariums and children moving about the room and talking.

Also contributing were street and playground noises and hallway and adjacent classroom noises that infiltrated the classroom. The noise was found to mask speech sounds and decrease speech perception abilities, resulting in decreased comprehension and reduced academic achievements, as well as increasing social-emotional problems. Other effects include increased voice fatigue for teachers and increased student listening effort.

Hearing aids had been around a long time, but in the school environment they were found to be counter-effective since all background noises were amplified. The study found that there were some basic nontechnical measures that teachers and administrators could take to improve acoustical conditions in classrooms. These included adding carpets or rugs, putting rubber tips on chair legs or using cushions in place of chairs. Other suggestions include putting drapes on windows and walls, using cork board on walls for bulletin boards to reduce reflective surfaces, using bookshelves as room dividers to create quiet classroom spaces, landscaping with trees and bushes to reduce outside noise, closing doors to hallways, using acoustic ceiling tiles and making sure lighting is adequate.

These common sense measures are all helpful in reducing unwanted noise, but don't address the fundamental need for increasing hearing capacity. High-tech was needed to solve that issue.

"What happened as a result of the MARRS study, is they took the single speaker on the desk and applied it to the entire room," Dobson explains. "Therefore, all the students could better hear the teacher's voice. This made a tremendous impact, and was promoted through the schools to make a big acoustic difference for all students, especially special needs."

But, continues Dobson, this wasn't as complete a solution as it might sound. The system was based on FM radio frequencies and the Federal Communications Commission only allows for so many of those frequencies. There were not enough to go around. Moreover, the frequency that is right for a student with normal hearing would not necessarily be right for a special needs student.

The breakthrough came in 1998, when researchers replaced radio frequencies with light frequencies, through the innovative use of infrared technology. "We invented the concept," says Dobson. It was patented and came to market in 1999. Now, explains Dobson, there is no interference between classrooms, and a student can easily adjust his or her device to get the appropriate auditory response to meet the student’s needs.

"The year 1999 was the turning point," continues Dobson. "For instance, now the Ohio Schools Facilities Commission requires this type of device in every classroom."

While Audio Enhancement created the infrared sound transmission system, it's not surprising that many other manufacturers have since created their own variations and added their own enhancements. One example is Extron Electronics. Mike Andrews, director of marketing communications, says that the path his company has taken is reconciling what has been the two disparate strands of improved audio and video.

In terms of its audio offering, Andrews refers to what he calls a "sound field," which means the system is designed to slightly amplify the teacher's voice using a microphone, audio amplifier and speakers placed strategically throughout the room. Young, inexperienced learners do not develop the ability to adjust their hearing in noisy conditions until they are 13-15 years old. For children, the teacher's voice needs to be approximately 15 decibels louder than the background noise in the classroom for high speech intelligibility. This decibel difference is called the Signal-to-Noise Ration (SNR). Comparatively, adults only require an SNR of four to six decibels. Research also shows that, not surprisingly, English as a Second Language (ESL) learners need a greater SNR than those whose native language is English.

But, says Andrews, while sound improvement has been improving on one track, so too has the visual aspect, although in a way that has not always been harmonious with sound. For video images come in from many different sources, projectors, DVD players, computers, including the Internet, documentary cameras and so on. Sound might be soft background music that might accompany an undersea video, but many others, such as history segments, require a greater precision with language.

The Trost Amplification Study of Canby School District, in Canby, Ore., indicates that use of these types of systems resulted in 43 percent fewer elementary students referred to special education; 15 percent higher scores on the Standard Achievement Test, including reading, language, math, science and social studies subtests; 21 percent higher scores on Oregon's Technology Enhanced Student Achievement test and a 35 percent increase in literacy test scores.

Improved technology seems to often result in greater ease of use and lower cost. This is the niche that Epson America, is making for itself, says product manager, Heather Litus Johnston. "We visited a number of different schools across the country and saw there were a lot of elaborate systems, but many were complicated to install and use, so we went back to engineering to simplify things, and also bring the system down in terms of cost.

Oh, and what happened to the woman who started it all, Claudia Anderson?

"She retired in 2008 and sold her company to her kids," says Dobson.