Introductory Words to Citizens Oversight Committee for Classroom Acoustics


1. Environmental consequences

o There are three environmental factors important to learning in classrooms

  • adequate light
  • comfortable temperatures
  • low background noise and reverberation - i.e., classroom acoustics

o Environmental design requirements for the first of these (lighting) are very well understood and easily met.

o There are seldom, if ever, any environmental disbenefits (such as noisy ballasts for fluorescent lighting) from meeting these requirements which are so vital for visual communication in the classroom.

o The environmental design requirements for the thermal environment are also very well known and readily achieved (energy considerations are not included here.)

  • While not directly connected to communication in the classroom, unacceptable thermal conditions are a real handicap to learning as the LAUSD knows very well.
  • However, unlike lighting, there can be a very serious disbenefit coupled to the third environmental factor - classroom acoustics.
  • This disbenefit occurs when these systems produce excessive background noise and are located in an overly reverberant classroom. This degrades aural communication - the most critical communication path for learning in the classroom.

o The design requirements for proper acoustics in classrooms are well understood by specialists in acoustics, noise control and speech communication but NOT generally recognized or understood by education facility planners or designers.

Thus, these requirements are seldom incorporated in procurement specifications for air conditioning systems or interior furnishings (which govern reverberation).

  • The engineering methods to achieve low noise output of air conditioning systems for classrooms is also generally well understood by specialists in noise control but these methods are not universally recognized or applied by all equipment manufacturers.
  • All (or most) air conditioning manufacturers are members of trade and/or professional organizations which are aware of noise control requirements
  • All (or most) manufacturers are able to conduct themselves or through independent laboratories, proper noise performance tests to insure compliance with proper acoustic performance specifications.
  • Thus, to insure that the vital auditory communication link to the learning process in classrooms is not impaired by bad acoustics, it is vital that adequate acoustic performance specifications be included in the procurement process for air conditioning systems to be installed in classrooms.

2. Economic Considerations

Inadequate acoustic conditions in existing classrooms equipped with noisy air-conditioning systems can be restored to proper conditions by retrofit or replacement but significant added cost penalty that can be avoided by procurement of properly-designed equipment. In summary, today's classrooms, where development of excellence in our children through learning is so vital for tomorrow's society, are affected by three environmental factors.

o Proper lighting is well understood, easily achieved, vital for the visual communication path in learning and normally has no related environmental disbenefits vital to the learning process

o Proper thermal conditions, necessary for reasonable classroom conditions, are also well understood and easily achieved but this achievement can have serious disbenefits to learning if equipment noise or room reverberation is excessive. o Proper acoustic conditions, vital for the more important auditory communication path in learning, are not widely recognized by non-specialists.

o They can be achieved in the most cost-effective manner if proper acoustic performance specifications are included when acquiring air conditioning equipment or interior furnishings for classrooms.


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