Frequently Asked Questions
About Classroom Acoustics

What causes high noise levels and other acoustical problems in classrooms?

• Most noise problems are caused by excessively loud heating-ventilation-air conditioning units (HVAC)
• Other noise sources in the classroom include the lights, AV and electronic equipment, pencil sharpeners, aquariums, and children moving about the room and talking
• Street and playground noise from outside the building penetrates classrooms
• Hallway and adjacent classroom noise also infiltrates the classroom.

Who is at risk for learning problems due to poor classroom acoustics?

Crandell, Smaldino, and Flexer (1995) identified the following groups of students as at risk for learning problems in the classroom:

• Children with any hearing loss whether unilateral, bilateral, high frequency, minimal, or fluctuating
• Children younger than age 13
• Children who have articulation disorders
• Children who have language-learning problems
• Children who have learning disabilities
• Children who are non-native English speakers
• Children who have a history of middle ear infections
• Children who have auditory processing disorders

Collectively, this represents about 20% of all school-age children.

What are the effects of noise on hearing in the classroom?

• Masked speech sounds
• Decreased speech perception abilities
• Decreased comprehension of information
• Reduced academic achievement
• Increased social-emotional problems.

What are other effects of poor classroom acoustics?

• Increased voice fatigue for teachers (Allen,1995). An Iowa study found that the highest percentage of teacher absences was due to voice-related problems.
• Students’ listening effort increases (Ross, 1992). The energy that is put into trying to hear the teacher reduces the student’s ability to focus on what is being said.
• Developmental factors related to language capacity. These factors cause younger children to have more problems than older children.
• Students with hearing impairment listen through a filter created by their hearing loss:
  • hearing aids amplify all sounds
  • assistive technology improves signal-to-noise ratios
  • assistive listening devices are a necessity for most students with hearing loss.

What will it cost to improve classroom acoustics?

• Retrofitting poorly designed HVAC systems or installing wall, ceiling, or floor treatments costs two to five times more than proper original design and construction.
• Although the cost to provide proper acoustical environments is estimated to raise construction costs by 5%, the benefit-to-cost ratio over time when comparing the educational benefits of improved signal-to-noise ratios is estimated to be 40:1 (Lubman & Sutherland, 1999).

What can be done to increase awareness about the problems associated with classroom acoustics?

• Assemble school facilities personnel who are responsible for school facility planning, design, and remodeling along with school audiologists, building principals, teachers, parents, and others who are knowledgeable and/or interested in this problem; also include local architectural firms and acoustical engineers.
• Have a meeting to raise awareness of the problems, the pending ADA regulations on classroom acoustics, and to discuss plans for addressing the problem.

What can teachers and schools do to improve acoustical conditions in their classrooms?

• Add carpet or rugs to the floor; if this is not possible, put rubber tips or tennis balls on the chair legs or use cushions in place of chairs.
• Put drapes on windows and walls.
• Use cork board on walls for bulletin boards to reduce reflective surfaces.
• Use bookshelves as room dividers to create quiet classroom spaces.
• Landscape with trees and berms to reduce outside noise.
• Close doors to hallways.
• Suspend acoustical tile.
• Ensure that lighting is adequate.

References

Allen, I. (1995). The effect sound field amplification has on teacher vocal abuse problems. Paper presented at the Educational Audiology Association Summer Conference, Lake Lure, NC, June 1993.

Crandall, C., Smaldino, J., & Flexer, C. (1995). Speech perception in specific populations. In C. Crandall, J. Smaldino, & C. Flexer (Eds.), Sound field FM amplification (pp. 49–65). San Diego: Singular Publishing.

Lubman, D., & Sutherland, I. (November, 1999). Good classroom acoustics are a good investment for America. Paper presented at the 138th Annual Meeting of the Acoustical Society of America, Columbus, OH.

Ross, M. (1992). Room acoustics and speech perception. In M. Ross (Ed.), FM auditory training systems: Characteristics, selection & use (pp. 40–41). Timonium, MD: York Press.

This information was excerpted with permission from Appropriate School Facilities for Students with Speech-Language-Hearing Disorders, a technical report published by the American Speech-Language-Hearing Association in 2002.