Page 35 - Fall 2005

Standards News
THE CLASSROOM AMPLIFICATION CHALLENGE TO ANSI S12.60–2002
David Lubman
David Lubman and Associates Westminster, CA 92683
Purveyors of sound amplification systems are mounting a very serious threat to the classroom acoustics standard—ANSI S12.60- 2002. As discussed below, these amplification systems address some of the same issues as the American National Standards Institute (ANSI) standard but provide limited benefits.
America wants to improve the educational achievement and inclusive- ness of its schools, and implementation of the ANSI standard promises this. ANSI-compliant schools are far friend- lier places for teaching and learning than noisy schools. ANSI-compliant schools are also more inclusive, accom- modating the needs of millions of mainstream students who are disad- vantaged by mild hearing, language, or other learning disabilities.
One reason for the large number of disadvantaged mainstream students is that America is once again a nation of immigrants. English language learners must hear and understand spoken words in classrooms as a prerequisite to learning. Yet, an estimated two-thirds of American classrooms fail to meet minimum requirements of the ANSI standard. The burden of that failure falls first upon disadvantaged students, teachers, and parents. Ultimately, the cost is borne by all.
Today’s challenge is to bring about widespread implementation of the ANSI standard. Implementation seems daunting to schools. For decades, American schools operated with weak noise guidelines such as the California Department of Education’s 50-dBA classroom noise limit—or none at all! After decades of disregard- ing the importance of acoustics to learning, favorable buzz about the standard is awakening schools to the benefits of good acoustics. Some school authorities now actually desire good acoustics, but fear the costs and
“The ... choice ... is between amplified classrooms with poor acoustics and unamplified ANSI-compliant classrooms”
How did the amplifier challenge come about? For years, vendors provid- ed classroom amplification systems to satisfy the need for elevated speech lev- els in special education rooms for hear- ing-impaired students. Perhaps to enlarge that limited market, some ven- dors of “free-field systems” (as class- room amplifiers are termed) are now aggressively promoting their use in mainstream classrooms.
There are too many mainstream classrooms in which students cannot understand what their teacher is say- ing because of noise and reverbera- tion, and where teachers suffer vocal fatigue from the effort of speaking above classroom noise. These situa- tions arise because of poor classroom acoustics. These are the very problems the ANSI standard is meant to prevent or remedy. Are amplifiers a valid alter- native for good classroom acoustics?
Actually even classroom amplifiers work better with good acoustics (low noise and reverberation). But amplifiers are unsatisfactory substitutes for good acoustics. We believe it is wrong to pro- mote amplifiers as universal panaceas for all classroom acoustical problems.
Advocates of good classroom acoustics claim improved student achievement and behavior and reduced teacher voice fatigue. Amplifier hawkers cite testimonials and studies claiming the same educa- tional benefits for amplifiers. The real choice schools are making is between amplified classrooms with poor acoustics and unamplified ANSI-com- pliant classrooms. Here is a short list of the advantages of ANSI compliance versus amplification.
• ANSI-compliant classrooms don’t need amplifiers. Students and teachers hear each other without strain or fatigue.
• Amplification has limited benefits
technical challenges of designing and renovating schools to satisfy ANSI’s 35-dBA noise limit.
Classroom acoustics advocates are pleased that the ANSI standard is awakening schools to the acoustical needs of students and teachers. Unfortunately, in earlier battles over approval of the standard, industry adversaries spread disinformation to school administrators and state legis- latures outrageously exaggerating the cost and challenge of compliance with ANSI’s 35-dBA noise limit. This made schools vulnerable to slick hawkers of amplifiers that promise good speech intelligibility and teacher voice relief without meeting ANSI requirements for low noise and reverberation.
To paraphrase H.L. Mencken’s observation, for every problem there is a solution that is fast, painless ... and wrong! Classroom amplification is a quintessential example of Mencken’s observation. Unfortunately, many school decision makers don’t see through the honeyed words of amplifi- er salespeople. Many choose the class- room amplification “band-aid” over good acoustics.
We agree that amplifiers are need- ed in auditoriums, very large lecture rooms, and in special education rooms for hearing-impaired students. But we cannot justify their use in small lecture rooms intended for mainstream stu- dents. And we deplore their use as a substitute for good acoustics.
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