There is no question that if a school had poorly lit classrooms that there would be an outcry and a demand to improve lighting so that children could clearly see to learn. Substandard classroom acoustics are not as obvious as the lighting analogy above although the effects of poor classroom listening may be even more significant than those caused by poor lighting. It is an assumption in education that children who are paying attention in the classroom will be able to easily hear what the teacher says, and thereby learn. For too many children, this assumption is untrue.

Realities of Classroom Acoustics
Appropriate acoustic treatment in classrooms costs 1%-5% of the typical construction budget of a new school – less than the landscaping. In general, providing appropriate classroom acoustics is not a considered a priority.

National standards for classroom acoustics were established by the American National Standards Institute (ANSI) in 2002. Research indicates that only 10%-30% of classrooms meet these standards In a national survey of schools almost 30% of classrooms were judged to be too noisy by educators.

The students who are most challenged by excessive noise and reverberation are under the age of 13, especially those in kindergarten and first grade. The auditory physiology that allows humans to effectively listen in relatively noisy conditions does not mature until secondary school, with some aspects not maturing until the end of high school. Our youngest students are also those with immature language learning and lack the words needed to expertly fill in the blanks when a new word or word ending is missed. Because adults are so much better at listening effectively in noise and reverberation, the impact of the acoustic environment is almost always underestimated by teachers, administrators and parents.

Veteran teachers too often believe that when they talk loudly the noise will not be a problem to students who are paying attention. When you raise your voice the louder and longer vowel sounds are heard more clearly, but the consonants stay weak (you cannot yell an /s/ or /f/ sound). We need to hear the higher pitch, quieter consonant sounds clearly to tell the difference between words such as cat, cap, cast, calf. Unfortunately it is the quieter high pitch speech sounds, typically consonants that are most easily covered up by noise and smeared by reverberation.

The effects of a poor acoustic environment are indeed insidious. In noisy and/or reverberant classrooms the least effects are seen when students are involved in practicing skills they already know, like math drill problems. The greatest effect is seen when students are introduced to new words or concepts. There is little wonder why some schools with similar student demographics are able to move through a curriculum more quickly while others are mired in a slower pace with a need for more repetitions, more questions, and more class time to learn the same concepts.

Even more insidious is the finding that children who are educated in noisy classrooms tend to give up faster when faced with learning challenges. This lack of perseverance is a serious limitation to a healthy learning attitude and our current need to be accountable for every child’s school achievement. It is not surprising that students in schools next to noisy freeways or under airport approach flight paths can have a 1 year drop in grade equivalent achievement scores for every 10 dB increase in traffic noise in the classroom. Finally, there exists the belief that when a teacher speaks quietly or when noise is present that the children will be encouraged to tune in and focus more intently. This may be true in the short term, but children in noisy educational settings learn to tune out – not tune in. The energy needed to listen more carefully leaves less mental capacity to process the information that is being presented and saps the length of time that students can truly employ. Noisy classrooms tend to be wigglier and require more repetition than in classrooms where children do not have to put as much effort forth to listen.

So What Can be Done?
Bring the idea of acoustics and the effect on student achievement to the attention of your administration. If one of the cornerstone foundations of learning is not sufficient it is no wonder that some schools are struggling more than others, even with the same student demographics present.

There is no ‘simple fix’ that will erase the effects of poor classroom acoustics. The key is the background noise present in the classrooms, which must first be reduced. To help achieve lower levels it is necessary to install good acoustic ceiling tile, consider switching to quieter HVAC systems and, in noisy communities, installing better windows.

In certain circumstances, putting a microphone on the teacher and loudspeakers in the classroom is a simple idea that can have a big impact on student attention and learning. Think of how the overhead projector helps all students see clearly what is written. Sound field amplification improves the loudness of the teacher’s voice over the background noise. Beware – in classrooms where there is a high level reverberation time then sound field amplification can actually be more detrimental to listening and the smearing of speech sounds.

Finally, educators and school administrators need to be aware of the effects of classroom acoustics on the successes and the struggles of students. Achievement is multifaceted and listening to learn is a cornerstone foundation to learning.

Karen Anderson PhD can be reached at or

Karen L. Anderson, PhD
Abridged by Alan R. Ehrlich – Please click here to read the full version of this important paper from Dr. Anderson’s website.
Written October 2007