Page 36 - Fall 2005

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in non-ANSI-compliant class- rooms.
Amplification inhibits class- room spontaneity. Students must overcome inhibitions and request or wait for a micro- phone. They must be also taught effective microphone skills, which is especially diffi- cult in lower grades.
There are problems and limita- tions of indiscriminate installa- tion. One example: amplifiers are often installed in excessively reverberant classrooms where amplification is known to be ineffective. Another example: high levels of amplified sound leak through poorly insulated walls to interfere with learning in adjacent classrooms.
ANSI compliance is a pay-once solution. Amplifiers have con- tinuing costs.
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It may be true that the costs, effort, and time needed to achieve ANSI com- pliance in classroom renovations
exceed the initial cost of classroom amplifiers. The false perception that amplifiers are a fast and inexpensive solution to all classroom acoustic prob- lems is exploited by amplifier salespeo- ple. Without knowledgeable persons to challenge these claims, who can blame school administrators for falling for the pitch? This may explain how amplifier lobbyists in Ohio evidently secured leg- islation ensuring that all future class- rooms in their state are pre-wired for amplifiers. We believe that Ohioans— and all Americans—would be better served by legislating ANSI-compliant classrooms.
Bridget Shield of London’s South Bank University was asked recently about her experience with classroom amplification in the UK. Her answer was devastating:
“What we are finding is that most of the systems ... are not used or are used incorrectly as they have broken cables or have not been installed cor- rectly or teachers have not been trained in their use. Or ... they are installed in
rooms with poor acoustics where they are ineffective and the rooms should be acoustically treated.”
With time and experience, schools will overcome their fears of the costs of ANSI compliance. This will make them less vulnerable to the false panacea of classroom amplification. But in the short run, advocates of good classroom acoustics must spread the word. We need to get our message to school deci- sion makers as compellingly as amplifi- er vendors and lobbyists: Classroom amplification is not a substitute for good acoustics.AT
David Lubman is an acoustical consultant/scientist in Orange County, California specializing in architectural acoustics and noise. He was co-chair (with Louis C. Sutherland) of the ANSI working group that developed the influential classroom acoustic stan- dard, ANSI S12.60-2002.
Lubman’s research helped standard- ize sound power measurements that is now widely used for rating HVAC equip- ment noise. He was senior editor of the book Acoustics of Worship Spaces, pub- lished by the American Institute of Physics in 1985. He is a founder of a new acoustical field, archaeological acous- tics. A Fellow of the Acoustical Society of America, Lubman served in many elect- ed and appointed positions in the acoustics community. He was an ASA Executive Councilman and chaired its technical committee on Architectural Acoustics. In May 2004, Lubman was awarded the Society’s Helmholtz- Rayleigh Interdisciplinary Silver Medal in Acoustics. He now chairs the National Council of Acoustical Consultant's Honors and Awards Committee.
34 Acoustics Today, October 2005