Sound Solutions


Poor classroom acoustics areimpairing students’ hearingand their ability to learn. Theneed for audio amplificationsystems is coming throughloud and clear.

Sound Solutions

"The square of the high moose he calls some of the squares of the other two sides.” Some students will tell you that’s the Pythagorean theorem. No, they’re not dumb; no, they don’t have attention deficit disorder; and no, their teacher doesn’t enunciate poorly. In many instances, even if they sit just six feet away from the speaker, they simply can’t hear.

The problem isn’t one of volume. In fact, what usually happens in a classroom when students say they can’t hear is that the teacher speaks louder. That may be fine for vowels, but it doesn’t do much for consonants— and it’s generally the consonants that provide the intelligibility: An oo ee i ats o? (Can you see why that’s so?) And even a loud voice isn’t likely to make it to the students in the back row if the classroom has bad acoustics. The only tangible result is usually teacher vocal strain.

Rather, student hearing difficulties are largely the result of three factors:

  • A child’s auditory neurological network isn’t fully developed until around age 15. For purposes of comprehension, children require louder voices and a quieter ambience than adults do.
  • Classrooms are noisy. There’s noise from other students, from computers and printers and lights and heating systems, and from people in the hallways and traffic outside.
  • Students don’t have the experience to “guess” at what they hear. If they don’t know the word hypotenuse, then they can’t process hearing “high moose” as anything but “high moose”—they can’t make the connection. And this is exacerbated if the student isn’t a native English speaker or really does have a hearing deficit.

The main problem, as Debbie Tschirgi, director of educational technology programs for Educational Service District 112 in Vancouver, WA, explains in her widely referenced white paper, “Classroom Amplification Systems: Understanding and Overcoming the Acoustical Barriers to Learning,” is inadequate signal-to-noise ratio in US classrooms, which impedes communication. She says that while the American Speech-Language-Hearing Association recommends a classroom noise level no higher than 30 decibels, the typical classroom has noise levels that range from 41 to 51 dB. (Keep in mind that loudness is measured on a logarithmic scale: A 40-dB classroom is 10 times as loud as a 30- dB classroom.) Tschirgi’s research indicates that for teachers to communicate well, their voices—or signals—should be 15 decibels more than that of the background noise, a “score” of plus 15. But she finds that most classrooms have signal-to-noise ratios ranging from minus 7 to plus 4.

A multiyear study conducted by Orange County Public Schools in Orlando, FL, “High Performance Schools Equals High Performing Students,” provides a summary, damning state of affairs: “Research has shown that a typical classroom provides an inadequate environment when auditory learning is the primary tool of instruction. As many as one-third of all students miss 33 percent of verbal communication in a typical classroom."

Hearing Is Believing

Technology has come up with a solution: tools that focus voices in a way that minimizes intrusive ambient noise and gets to the intended receiver—not merely amplifying the sound, but also clarifying and directing it.


Propelled by her son’s own classroom auditory troubles, one parent became an advocate for sound enhancement technology.

Sound SolutionsChristopher DeMallie was in kindergarten when he began to struggle in school. He couldn’t sing the alphabet song; he misused his pronouns; he wouldn’t participate in “circle time”; and in general, he’d become upset whenever the conversation turned to school. Searching for a solution, his mother, Suzanne, took Christopher to a pediatrician, a psychologist, and finally an audiologist. The audiologist concluded that Christopher had a “temporal processing deficit”—sounds got distorted on the way to his brain.

Christopher’s teacher placed him away from open windows and doors so the ambient noise wouldn’t interfere with his hearing, and his mother got him some private speech therapy. Today, three years later, Christopher is fine, deficit-free.

As a result of her experience with her son, Suzanne began to educate herself on hearing problems. She discovered that students who couldn’t hear well and thus became distracted or disinterested were sometimes being misdiagnosed with attention deficit disorder (ADD) and attention deficit hyperactivity disorder (ADHD), and even being prescribed Ritalin, when what was needed was a better classroom environment. Her research showed her that classroom acoustics were typically to blame. DeMallie concluded that children with much better hearing than her son were still facing auditory deficits in school.

She started her own organization last summer, the Institute for Enhanced Classroom Hearing, in Towson, MD, with a mission to “improve the auditory classroom environment through integration of classroom sound enhancement technology.” DeMallie sees the research into the benefits of sound amplification systems as conclusive (“It’s a no-brainer”), the cost as manageable (“It’s a lot cheaper than retrofitting the classroom”), and the need universal (“This problem affects every child every day in every classroom”).

The cost of enabling every student in a classroom to hear clearly is not as daunting as it may seem. For an adequate sound amplification system, DeMallie recommends “an infrared model with four speakers and a pass-around microphone for the students, at an approximate cost of $1,500 to $1,700, which should include professional installation and in-service training.” According to DeMallie’s calculations, that averages out to 16 cents a day per pupil (given 25 students per classroom). And, she adds, the sound system is used about five hours per day, not just a sporadic few minutes here and there, as other classroom technologies such as a TV/VCR are used.

“When research overwhelmingly supports an educational need that is financially justified and reasonable,” she says, “we as a society owe it to the children to supply them with that resource. Every child deserves a chance to hear the teacher. Every teacher is important enough to be heard.”

One provider of classroom audio technology is Audio Enhancement, which has a manufacturing relationship with Panasonic. Using an Audio Enhancement system, teachers speak into a microphone, and speakers transmit the voice throughout the classroom. Teachers can also hook up the system to computers, DVD players, VCRs, interactive whiteboards, and just about any other classroom tool. They can capture audio and put it on the internet. They can even tie everything into the school’s public address system.

For example, Audio Enhancement’s CAE-100W classroom audio system, called “The Innovator,” comes with four infrared microphones, multimedia mute control, and a PC user interface. Teachers can use a remote control to modulate the volume of their own microphone, the students’ microphones, and the auxiliary inputs. The entire product consists of four ceiling speakers, a receiver, handheld student microphones, a pendant teacher microphone, a dome sensor, a cable, and a charger. It costs about $1,200 a classroom.

So, for about a grand, the teacher can always be heard clearly, anywhere in the classroom. When students participating in discussions use the microphone, they too can be heard clearly, anywhere in the classroom. And the same is true of any audiovisual presentation, from films to tapes to podcasts.

“[The sound system] wasn’t just making it louder and blaring. He was talking very naturally. I thought,Wow, this is making a difference.”
—Kate Clark, Ocoee Middle School

Interestingly, one person who needed to be convinced of the need for the technology is now the company’s vice president of emerging technology, Jim Snyder, who was previously the CTO of Lake County Schools in Florida. “When I first heard about [these systems],” he says, “I said, ‘No way; the teacher doesn’t need a microphone.’” But the act of installing one into classrooms made a believer out of Snyder. Lake County teachers who tried it out on a demo basis didn’t want it removed: "Everyone who used it swore by it,” he says. The district’s schools found that teachers’ absentee rates were down because the teachers had more energy and weren’t harming their voices.

Another doubter turned convert is Kate Clark, the principal at Ocoee Middle School in Florida. Ocoee is about 10 miles north of the Disney complex, with more than 1,700 students. The school began using Audio Enhancement systems in the 2000-2001 school year. Like Snyder, Clark was skeptical.

“I was a real naysayer at first,” she says. “It was the most ridiculous thing I ever heard of.” But then she attended a meeting about the new product in a conference room, and the speaker was turning the system on and off. “It wasn’t just making it louder and blaring,” she says. “He was talking very naturally. I thought, Wow, this is making a difference.” She began looking at the research and soon became a proponent.

Ocoee tried out the system in two very different places: in an old science room with wood cabinetry and hard surfaces, and in a portable classroom with carpets. Regardless of the surface areas, the audio was distinctly enhanced. “It was phenomenal,” Clark says. Both teachers got to keep their systems beyond the planned two weeks.

Clark enthuses about the changes in the school. Teachers, their voices saved from overwork, tell her they have as much energy in sixth period as they do in first period. Some of her shy bilingual students have taken to speaking with the microphone. “It made them more confident,” she says. She has seen a huge gain in test scores. Sometimes, she says, teachers take their microphones with them to lunch and forget to turn them back on when they return to class—but the students invariably tell them. Ocoee has audio speakers in classrooms, in the band and chorus rooms, in the media center, and in the gym. “It has made the biggest difference in the world,” Clark says. “Teachers would overwhelmingly pick this as the best technology they have.”


IN HER WHITE PAPER on classroom sound systems, Debbie Tschirgi, educational technology program director for Educational Service District 112 in Vancouver,WA, advises schools to ask manufacturers of sound technology some important questions before making a purchase. For example:

  • Do you provide infrared or radio-frequency systems?
  • How do you address the masking of the weaker, higher-frequency sounds, such as consonant sounds?
  • What are the options for microphones? Where can they be placed? How many can be used simultaneously?
  • How can your product tie in with other systems in the classroom, for example, computers, VCRs, and DVD players?
  • What are the options for speakers? Where can they be placed?
  • What’s the average life of batteries used in the microphones?

Measured Progress

Bruce Bebb says that in the near future people will find this kind of audio enhancement as natural and essential as good lighting. He’s the marketing communications director of LightSpeed, based in Tualatin, OR, and a former elementary school principal. LightSpeed’s Infrared Classroom Amplification Technology (REDCAT) device is another wireless infrared classroom ampli- fication system. It costs about $1,000 a classroom.

“You basically pull it out of a box and set it anywhere in the room within minutes,” Bebb says. One flat-panel speaker (22 inches long, 10.5 inches wide, and 3.25 inches deep) projects the sound, but Bebb says that “you are hard-pressed to point to where the sound source is.” His demos have ended much as Snyder’s and Clark’s: After seeing the device at work, everyone in the audience wants one.

Bebb cites the Trost Study, an independent study of Light- Speed systems installed in Canby, OR’s Trost Elementary School, carried out by the Canby School District. Some of its findings from amplified classrooms:

  • 35 percent higher first-grade scores on the Dynamic Indicators of Basic Early Literacy Skills (DIBELS)
  • 35 percent higher words-per-minute reading scores by fourth- and fifth-graders
  • 21 percent higher scores on the Technology Enhanced Student Assessment, a standardized test given by the Oregon Department of Education
  • 72 percent decrease in teacher redirections
  • 43 percent decrease in off-task student behaviors

Those numbers would come as no surprise to Patrick Mahaffey, a third-grade teacher at Carlsbad, CA’s K-6 Olivenhain Pioneer Elementary School. He’s been using an audio system from Califone International for years. He can offer confirmation of the relief that audio systems give to teachers’ voices—his voice no longer gets worn out the way it once did. He also observes that children with attention deficit disorder “tend to have a little longer period of focus time” with the amplified sound. His only issue is that he sometimes forgets to turn off the microphone when he goes to counsel a student one-on-one; other students point out the error soon enough.

Another Califone user is Steve Lewey, the project manager in the technology department of Lake Washington School District, just north of Seattle. He’s had the company’s speakers installed in every classroom in the district—1,400 of them. The district uses the speakers as part of its projection system—computer, ceilingmounted projector, DVD player, and VCR. “The system as a whole,” says Lewey, “has got the students more engaged.”

Califone develops products for auditoriums as well as classrooms. For example, the Presentation Pro 300 line—an amplified 30-watt speaker with built-in receiver, microphone, tripod, remote, and case—sells for about $365. “We’ve got 60 years of making audio products specifically for schools,” says Tim Ridgway, the California-based company’s vice president of marketing. Ridgway explains that the amplification systems keep the sound from bouncing off the classroom walls or ceiling, and instead keep it focused on the students. “What that means,” he says, “is that it effectively increases the signal-to-noise ratio.”

Sounds Good to Everyone

A study released this past March, “Improving the Classroom Environment: Classroom Amplification Systems,” done by Miami-Dade County Public Schools, spells out the general benefits of audio systems to students and teachers, namely, increases in student attention, participation, productivity, comprehension, and on-task behaviors, and a decrease in discipline problems.

The report also alludes to additional studies of the health benefits for teachers in sound-amplified classroms, one that found a reduction in teacher sick days because of voice, jaw, or throat problems, and another that reported a 25 percent decrease in teacher absenteeism.

Debbie Tschirgi’s white paper provides more impressive specifics. Tschirgi cites a study conducted by Laurie Allen, an educational audiologist in Dubuque, IA, who surveyed 334 students in grades 1 to 6 about amplified classrooms. The study found that:

  • 93 percent of students liked when the teacher used the sound system.
  • 95 percent said it was easier to hear the teacher when the speakers were on.
  • 87 percent said they do better when the speakers are on.

Tschirgi points out that although classroom amplification systems have long been used to help hearing-impaired students, the research indicates that there are benefits in store for students with normal hearing ability also. She writes, “The rationale…is simple: How well children hear their teacher affects how well they learn…. Sound amplification is a cost effective way to improve classroom acoustics so that all students can learn to their potential.”

As ever, though, the best testimony comes from the audience of student users. Cassandra, a sixth-grader at Ocoee Middle School, says that the poor acoustics in her in elementary school classroom caused her “to miss a lot of things,” even though she has no medical hearing problems and usually sat near the front of the room. After class, she’d ask the teacher to repeat some of the information, but it wasn’t as good as getting it the first time. Alexis, an Ocoee eighth-grader, says that in addition to all the noise in her elementary school classroom—such as air conditioning— sometimes teachers would turn their backs when writing on the blackboard, and it would be even more difficult to hear them.

At Ocoee, things are different. Alexis says that when she first came into an audio-enhanced room, “I was pretty surprised— you could hear throughout the whole entire room.” And Cassandra says that audio enhancement “made note-taking a lot easier for me.” She explains that particularly in science class, students have to watch PowerPoint presentations and listen to the teacher at the same time; audio enhancement makes it easier to do that. “It really does help the kids out,” she says. “It really does make a difference.”

:: web extra ::For more information on this topic, visit T.H.E. Journal and search by the keyword audio.

Neal Starkman is a freelance writer based in Seattle.

This article originally appeared in the 06/01/2007 issue of THE Journal.