The architectural design of a classroom includes room size, room shape, and surface treatments. Suitable acoustical design in classrooms and other learning spaces enhances speech clarity and limits background noise to protect speech quality for both students and teachers. Poor acoustical design can result in excessive noise that is disruptive to the learning process and may negatively affect speech perception, student behavior, and educational outcomes (Klatte, Hellbrück, Seidel, & Leistner, 2010; Klatte, Lachmann, & Meis, 2010; Shield & Dockrell, 2008). Poor acoustics can affect all students, not just those with hearing loss.
Improving acoustics in classrooms used by children with hearing problems is important. There are also benefits for individuals in the classroom with typical hearing. Examples include the following individuals:
On a related note, teachers who can use a natural teaching voice free from vocal strain may also benefit from improved classroom acoustics (Kristiansen et al., 2014).
Classroom noise includes any auditory disturbance that interferes with what a listener wants and/or needs to hear, including
Audiologists, acoustical consultants, speech-language pathologists (SLPs), classroom teachers, teachers of the Deaf and hard of hearing, and administrators may work as a team to improve acoustical conditions in classrooms and other learning spaces. See the American Speech-Language-Hearing Association's (ASHA) Scope of Practice in Audiology (ASHA, 2018) and Scope of Practice in Speech-Language Pathology (ASHA, 2016b).
Appropriate roles and responsibilities for audiologists in relation to classroom acoustics include the following:
As indicated in the Code of Ethics (ASHA, 2016a), audiologists who work in this capacity should be specifically educated and appropriately trained to do so.
Appropriate roles and responsibilities for SLPs in relation to classroom acoustics include the following:
As indicated in the Code of Ethics (ASHA, 2016a), SLPs who work in this capacity should be specifically educated and appropriately trained to do so.
There are several stakeholders with interest, knowledge, and skills in classroom (and other learning space) acoustics. These stakeholders include classroom teachers, teachers of the Deaf and hard of hearing, school administrators, and acoustical consultants. See ASHA resources on Interprofessional Education/Interprofessional Practice (IPE/IPP).
Classroom teachers are instrumental in identifying students who may be experiencing hearing loss or other types of listening problems and in referring those students to the appropriate professionals for further assessment. For students with identified hearing loss and/or listening problems, the classroom teacher may need to implement accommodations and strategies within the general education environment(s). Building administrators can be instrumental in providing resources and collaborating with teachers to improve classroom acoustics and students' listening environments.
In classrooms where the acoustics are less than optimal, classroom teachers may find it beneficial/effective to use strategies that have typically been used for students with hearing loss, including
Acoustical consultants have a variety of educational backgrounds, including engineering and physics. Consultants use knowledge of room acoustics, noise control, acoustical isolation, and audio systems to ensure the efficient distribution of desirable sound as well as the suppression of undesirable sound in and around classrooms and other structures.
Examples of contributions made by acoustical consultants include the following:
Sound waves radiate in all directions from a source until they come to an obstacle (e.g., a wall). The intensity of a sound wave is a measurement of perceived loudness. The frequency of a sound wave is a measurement of perceived pitch.
Both the intensity and the frequency of the sound wave will affect the sound–surface interaction. When sound waves strike a surface, one or more of the following can occur (Seep et al., 2000):
Transmission—sound passes through the surface into the space beyond it.
Absorption—the surface absorbs the sound.
Reflection—the sound strikes and bounces off of the surface. Reflected sound can result in echoes, which can interfere with hearing and understanding speech. Echo types include
Diffusion—the sound strikes the surface and is scattered in many directions.
Several types of measurements may be considered when assessing a room's acoustical environment. Measurements can be taken in occupied or unoccupied rooms and compared to ANSI/ASA standards.
Reverberation time (RT)—a measurement of how quickly sound decays in a room, depending on the physical volume and surface materials of a room. The RT60 of a room is the time in seconds it takes for a sound of 60 decibels to die down completely.
Noise reduction (NR)—a measurement of the effectiveness of materials to decrease sound exposure. The NR of a wall measures the percentage of sound produced in one room that passes through the wall into the next room.
Noise reduction coefficient—a measurement of the ability of a material to absorb sound.
Signal-to-noise ratio (SNR)—a comparison of a desired signal (sound) to the level of background noise. This measurement can be used to determine the level of speech intelligibility within a room (and in specific parts of a room). A positive SNR indicates that the signal of interest is louder than the background noise. In general, the more positive the SNR, the better the speech intelligibility.
Noise criterion (NC)—a measurement of relative loudness in a room with a range of frequencies. NC can be used to rate indoor noise (e.g., equipment noise).
Poor classroom acoustics can affect speech intelligibility (percentage of understandable speech) potential within a given learning space.
Educational audiologists and/or acoustical consultants are responsible for assessing classroom acoustics and associated student performance within the classroom. They are uniquely positioned to take acoustical measurements in the classroom and compare them to ANSI/ASA or other standards.
Acoustical assessments of classrooms and of student performance within their learning environments may include
Both audiologists and SLPs may be involved in gathering behavioral performance measurements, assessing changes in student behavior, and making recommendations regarding improving the listening environment.
A classroom acoustics survey can help determine whether corrective action is needed. Recommendations are devised to meet acceptable criteria to the extent practical. Strategies for improving acoustical conditions may include
Members of the school staff and the district's facilities department may collaborate to improve acoustics. Measurements taken before the recommendations are implemented can be repeated after changes have been made to determine and document the effectiveness of the changes and improvements over time.
Classroom audio distribution systems (CADS), formerly referred to as sound-field amplification systems, provide benefits to all listeners in a classroom. The ASA Panel on Public Policy (2013) states that “provided that sound field amplification systems are used in conjunction with ANSI S12.60, the ASA recognizes their usefulness for core classrooms to augment teachers' voices as multimedia sound distribution systems” while noting that they should not be used as a replacement for suitable room acoustics.
When a CADS is considered, it is important to carefully assess the classroom acoustics and follow a systematic process to determine the most appropriate solution for a given classroom. Classroom acoustics are a significant factor influencing the efficacy of CADS (Dockrell & Shield, 2012).
Children with hearing loss may require personal frequency modulation (FM) systems for the best results, despite any CADS that may already be in place (Wolfe et al., 2013). In fact, in some cases, a CADS may negatively affect the results of a personal FM system (Wolfe et al., 2013). Involvement of an educational audiologist is important when considering, choosing, and installing a CADS, as well as when training is provided.
Modifications to the physical characteristics of a room or other learning space can improve the acoustical quality. It is important to consider the sound absorption qualities of various absorptive materials for ceilings, walls, and floors. An absorption coefficient and a noise reduction coefficient are used to measure the ability of a material to absorb sound (Seep et al., 2000). Examples of classroom modifications are listed below. Additional and more specific details can be found in classroom acoustical resources and guides (Canning et al., 2015; National Deaf Children's Society, 2016; New Zealand Ministry of Education, 2016; Phinney & Woolworth, 2015; Seep et al., 2000).
Acoustical panels on the ceiling may help improve the listening environment in the classroom, especially if there is a high ceiling. Any acoustical ceiling tile that is used should have a sound absorption coefficient rating sufficient to achieve the desired noise and/or reverberation reduction.
Where practical, installing carpet over a pad to absorb sound and dampen noise from students and from movement of classroom furniture is beneficial.
Classroom furniture and movable screens can be used and manipulated to provide acoustical separation and break up sound reflections. Using felt or rubber caps on chair and table legs may help reduce noise as well, particularly if floors are not carpeted.
Some fluorescent lighting systems emit a constant noise. Regular maintenance—and, when possible, the use of high-frequency lighting—can reduce and/or eliminate flickering and buzzing.
High ambient noise from mechanical equipment—such as noisy HVAC systems—can be mitigated by adding custom-built enclosures around mechanical units, adding sound-lined ductwork to the unit, and addressing the location of the HVAC systems in relation to the learning spaces. Equipment such as computers, projection units, and aquarium pumps add to mechanical equipment noise.
Strategies for mitigating noise through modifications to existing walls include adding materials such as fabric-faced glass fiber wall panels, carpet, sound-absorbing panels, or acoustical ceiling tiles to the walls.
Strategies for mitigating noise through modifications to windows and doors include adding double-pane or storm windows, tight-fitting solid core doors, and window draperies/shades.
Exterior noise also contributes to the background sound in a classroom. Modifications to reduce exterior noise include using exterior barriers and landscaping to deflect or absorb unwanted sounds and ensuring that building walls are free of cracks and receive regular maintenance.
Acoustical design begins at the outset of the building planning, design, and construction process. It is likely easier to incorporate appropriate acoustical materials at the beginning of the process, rather than retrofit materials at a later date. A new school building's architectural team may employ acoustical consultants to evaluate aspects of the design, such as interior room acoustics, acoustical isolation, and mechanical system noise control.
Acoustical consultants may advise on the following:
The ANSI/ASA S12.60-2010 series of standards includes the following:
These standards, based on the best scientific evidence available at the time of publication, “help school planners and designers provide good acoustical characteristics for classrooms and other learning spaces in which speech communication is an important part of the learning process” (ANSI/ASA, 2010, p. 2).
Standards include guidance on
Guidelines and requirements for classroom construction and applicable facilities are determined on the state and local levels. International and national model standards are developed by the International Code Council and then are adopted by states or localities. In some states, guidelines are uniform; however, many states use guidelines as a basic blueprint. State requirements regarding standardized classroom size, materials, construction requirements, lighting, and similar factors may be found in the information regarding capital construction and/or building requirements available from the state's department of education.
This list of resources is not exhaustive and the inclusion of any specific resource does not imply endorsement from ASHA.
American National Standards Institute/Acoustical Society of America. (2009). S12.60-2009/Part 2: American National Standard acoustical performance criteria, design requirements, and guidelines for schools, Part 2: Relocatable classroom factors. Melville, NY: Acoustical Society of America.
American National Standards Institute/Acoustical Society of America. (2010). S12.60-2010/Part 1: American National Standard acoustical performance criteria, design requirements, and guidelines for schools, Part 1: Permanent schools. Melville, NY: Acoustical Society of America.
Acoustical Society of America. (2013).Classroom acoustics policy statement. Melville, NY: Author.
American Speech-Language-Hearing Association. (2016a). Code of ethics [Ethics]. Available from www.asha.org/policy/
American Speech-Language-Hearing Association. (2016b). Scope of practice in speech-language pathology [Scope of practice]. Available from www.asha.org/policy/
American Speech-Language-Hearing Association. (2018). Scope of practice in audiology [Scope of practice]. Available from www.asha.org/policy/
Canning, D., Cogger, N., Greenland, E., Harvie-Clark, J., James, A., Oeters, D., . . . Shield, B. (2015). Acoustics of schools: A design guide. Milton Keynes, United Kingdom, and Northallerton, United Kingdom: Institute of Acoustics & the Association of Noise Consultants.
Dockrell, J. E., & Shield, B. (2012). The impact of sound-field systems on learning and attention in elementary school classrooms. Journal of Speech, Language, and Hearing Research, 55, 1163–1176.
Klatte, M., Hellbrück, J., Seidel, J., & Leistner, P. (2010). Effects of classroom acoustics on performance and well-being in elementary school children: A field study. Environment and Behavior, 42, 659–692.
Klatte, M., Lachmann, T., & Meis, M. (2010). Effects of noise and reverberation on speech perception and listening comprehension of children and adults in a classroom-like setting. Noise & Health, 12, 270–282.
Kristiansen, J., Lund, S. P., Persson, R., Shibuya, H., Nielsen, P. M., & Scholz, M. (2014). A study of classroom acoustics and school teachers' noise exposure, voice load and speaking time during teaching, and the effects on vocal and mental fatigue development. International Archives of Occupational and Environmental Health,87, 851–860.
National Deaf Children's Society. (2016). Creating good listening conditions for learning in education. London, United Kingdom: Author.
Nelson, P. B., Sacks, J., & Hinckley, J. (2009). Auralizing adult‐child listening differences. The Journal of the Acoustical Society of America, 126, 2192.
New Zealand Ministry of Education. (2016). Designing quality learning spaces: Acoustics version 2.0. Wellington, New Zealand: Author.
Phinney, P., & Woolworth, D. (2015). Classroom acoustics for architects. Melville, NY: Acoustical Society of America.
Seep, B., Glosemeyer, R., Hulce, E., Linn, M., & Aytar, P. (2000). Classroom acoustics I: A resource for creating learning environments with desirable listening conditions. Melville, NY: Acoustical Society of America.
Shield, B. M., & Dockrell, J. E. (2008). The effects of environmental and classroom noise on the academic attainments of primary school children. The Journal of the Acoustical Society of America, 123, 133–144.
Smaldino, J. J., Crandell, C. C., Kreisman, B. M., John, A. B., & Kreisman, N. V. (2008). Room acoustics for listeners with normal hearing and hearing impairment. In M. Valente, H. Hosford-Dunn, & R. H. Roeser (Eds.), Audiology treatment (pp. 418–451). New York, NY: Thieme Medical Publishers.
Wolfe, J., Morais, M., Neumann, S., Schafer, E., Mülder, H. E., Wells, N., . . . Hudson, M. (2013). Evaluation of speech recognition with personal FM and classroom audio distribution systems. Journal of Educational Audiology, 19, 65–79.
Content for ASHA's Practice Portal is developed through a comprehensive process that includes multiple rounds of subject matter expert input and review. ASHA extends its gratitude to the following subject matter experts who were involved in the development of the Classroom Acoustics page:
In addition, ASHA thanks the members of the Working Group on Acoustics in Educational Settings whose efforts were foundational to the development of this content. Members of the working group were Karen L. Anderson, Susan J. Brannen (vice president for professional practices in audiology, 2001-2003), Carl C. Crandell (co-chair), Peggy B. Nelson, Anne Seltz, Joseph Smaldino (co-chair), and Evelyn J. Williams (ex officio).
The recommended citation for this Practice Portal page is:
American Speech-Language-Hearing Association (n.d.). Classroom Acoustics (Practice Portal). Retrieved month, day, year, from www.asha.org/Practice-Portal/Professional-Issues/Classroom-Acoustics/.