Activities

It is still common for the teaching style to be like a lecture where the teacher leads discussions. In these cases their voice should comfortably reach out to the whole class without being strained while there should be a minimum of background and disturbing sounds.  

Acoustics

Reducing the sound levels is very important, particularly the low frequency sounds around 125Hz as this improves students' listening comfort. These low frequency booming sounds interfere with the clarity of speech. A reduction in sound levels filters out, among others, these unwanted low frequency sounds allowing listerners to receive the speech as the speaker intended. The clarity of speech is maintained by limiting low frequency powerful vowel sounds, thus supporting the consonant sounds. 

In larger classrooms/lecture rooms where the students sit more than eight metres away from the teacher, a speech reflecting zone should be added to the ceiling in order to ensure the teacher's speech carry to the back. Absorption placed on the back wall opposite the speaker avoids disturbing late sound reflections which impair the clarity of speech. Integrating bookshelves with sound absorbing wall panels can add further benefit by increasing the scattering and diffusion of the sound environment.