Fifth lesson of acoustics: Acoustic treatment in classrooms and lecture halls

The efficiency of oral communication in a teaching context, and therefore in a learning process, is closely related to the conditions of the environment.
The acoustic performances of a room are a key part of a high-quality design.

Link between acoustic performance and reverberation time

How does the performance change in lecture halls where the suitable acoustic comfort is not ensured?

Studies show how the margins of error of the students may be subjected to fluctuations even higher than 15% in an environment where the reverberation time causes a noise level of more than 60 dB. Below 55 dB the percentage drastically drops to 4,3%.
Sound clarity is closely linked to the “trail of sound” duration in a room, conventionally measured with the “reverberation time”. In the case of educational spaces, the reverberation should be balanced so as to strengthen the direct sound. An excessive reverberation together with a high background noise reduce the intelligibility of speech.

Trattamento acustico aule

The optimal value of reverberation time in a listening environment thus represents the right compromise between the reaching of a sound level sufficient to hear effortlessly and the absence of masking effects among the syllables of the message.

In this sense, the acoustic design of teaching rooms aims at the best comprehension of the spoken message. The interventions for the acoustic correction should envisage the use of different materials in order to allow the absorption of the relevant frequency range. A targeted distribution of the acoustic absorption in the place should also be planned to guarantee the same listening homogeneity into the whole room.
School is a very important application field where different acoustic parameters come into play and should be taken into account as they may significantly affect the quality of teaching. Speech intelligibility is thus a fundamental and essential requirement.