Acoustics

When noise levels in the classroom are too high, students and teachers lose the ability to intelligibly understand each other. Typical sources are outdoor sounds (traffic, airplanes, etc.), loud air conditioning and ventilation systems, and internal noise from other school spaces. The teacher and student's inability to hear one another directly affects student performance. Teachers must sometimes resort to shutting off the ventilation systems because they are too loud, which can have the unfortunate side effects of reducing indoor air quality and thermal comfort.

Students are particularly susceptible to the ill-affects of background noise. Age, instances of hearing loss, lack of language proficiency, and individual hearing preferences can all affect how well a given student can hear in the classroom. Approximately 15% of children are estimated to have a slight hearing loss, and investigations of school records has linked hearing losses with lack of progression through school. Typically, children do not fully develop the ability to sort sounds from background noise until they are teenagers.

Recognition of the widespread acoustic problems in America are spurring developments of a national minimum acoustical standard for classrooms which may be enforced under the auspices of the Americans with Disabilities Act. Typical low-first cost air-conditioning systems used throughout California do not meet the recommended levels for background noise. Location of HVAC equipment, duct design and internal surface choices all contribute to the overall acoustic performance of the space.