Acoustic challenges when designing schools

What does acoustics mean to you as an architect, and what effect does it have on education?

“Acoustics is a term adopted to define how sound travels in a room. While designing, there are many elements that produce loud or soft sounds, for example, flooring material, wall surfaces and air ducts. Acoustics is one of the primary influencing variables for when it comes to education. Some claim the inclusion of acoustics would benefit in enhancing the standard of Indian education.”

Why do you think that good acoustics is so essential to education?

“Hearing and understanding are predominant parts of the learning process. A noisy classroom can make these tasks challenging. Our five senses are the instruments of learning. Out of all the five senses, our education system maximally uses ears. Education has a long practice of being imparted through oral discourses. All the ancient Vedas, Shruti and Purans were taught through speech and listening discourses. Therefore, the quality of sound and the skill of listening are essential for learning.”

What are the risks of failing to create a better sound environment for teachers and students?

“Research shows that quieter classrooms improve academic performance, reduce stress for teachers, and better student behavior. A good classroom experience leads to increased productivity. And it creates a better quality of life and an improved sense of well-being for teachers and students alike.

Higher noise levels have proven negative effects on health. For students, it can lead to lower academic performance since students have to work harder in order to understand their lessons. And for teachers, higher noise levels can mean a loss of voice for having to talk louder to be heard. There is a higher risk of impaired heart functioning caused by a sustained increase in heart rate over time. Listening becomes a challenge, and teachers and students need to repeat themselves to get heard and listened to. The fact that humans are not great listeners from the beginning makes it more difficult – we usually only retain 25% of what someone says.”

What are the main causes and sources of acoustic disturbance in the classroom, and how does this distort sound in a classroom?

“There are multiple factors and circumstances that make it hard for children to hear and understand in the classroom. Two factors cause poor classroom acoustics: too much background noise and/or too much reverberation. Background noise is any sound that causes disturbance and makes it difficult to hear. In a classroom, background noise can come from many places, including pedestrian and street traffic noise from outside, or internal noises such as students talking or sound from AC units. On the other hand, reverberation describes how sounds act in a room after they first happen. Sound stays in the room when it bounces off desks or walls. If many sounds do this simultaneously, it can get very loud so this also becomes a disturbance.

If a classroom has poor acoustics, low-frequency sounds will distort speech. Sound will also bounce off ceiling and walls and create echoes. Sound levels will show a tendency to escalate, this is a well-researched phenomenon called the Lombard Effect. And both students and teachers will have to raise their voices to be heard, making them more likely to feel tired and unfocused.”

What do you think are the main needs of teachers and students in the classrooms that you design?

“Teachers and students have three wishes in relation to sound and noise in classrooms. They require:

1. Better speech perception. This is affected by the room acoustics. Good acoustics mean that the voice can easily reach the ears, as the sound waves are direct. There is no delayed sound heard in the room.
2. Better speaker comfort. As a standard, a reflective material is used in classrooms just above the speaker; The rest of the surface is of an absorptive material. For larger spaces, the back surface of the classroom is cladded with an absorptive material for the ease of the teachers.
3. Less noise. You cannot force children to be quiet, but by providing the right acoustic conditions in which to listen and learn, the teacher can focus on what matters.”

How do you meet these needs through the design process?

“In order to create optimal room acoustics, you must first consider what activities will take place in the room, the human sound preferences for those activities, and the type of room. The main factors you need to consider as a designer, is to reduce the disturbance from background low-frequency noise, make sure the entire school gets the proper acoustic treatment (learning doesn’t just happen in the classroom!). And to choose safe and sustainable products. Choice of materials is crucial when it comes to classroom acoustics, and also the environment.

My process is as follows:

• Use a sound-absorbing suspended ceiling with exceptional absorption qualities for all speech frequencies, and particularly low frequencies.
• Add wall absorbers on the back wall for traditional teaching, and on two adjacent walls for group teaching.
• Add a speech-reflecting zone in the ceiling above the teacher for traditional teaching.

These will ideally be supplied by a company which is able to prove, transparently, through Environmental Product Declarations (EPDs) that their products meet the highest standards for sustainability.

If this is achieved, the impact is sure to be a huge reduction in background sound levels and less build-up of echoes. This ensures higher levels of speech clarity, which means better speech perception and optimal speaker and listener comfort. And with the smallest possible environmental footprint.”

Author: Ar. Jatin Asher
Co-author: Ar. Tushita Mehta