Evaluation of acoustical conditions for speech communication in working elementary school classrooms

This paper describes the room acoustics characteristics and noise environment of 27 traditional rectangular classrooms from the 41 measured rooms. The purpose of the work was to better understand how to improve speech communication between teachers and students. The study found that on average the students experienced: teacher speech levels of 60.4 dBA, noise levels of 49.1 dB and a mean speech-to-noise ratio of 11dBA during teaching activities. The mean reverberation time in the occupied classrooms was 0.41 s, which was 10% less than in the unoccupied rooms. The reverberation time measurements were used to determine the average absorption added by each student. Detailed analyses of early and late-arriving speech sounds showed these sound levels could be predicted quite accurately and suggest improved approaches to room acoustics design.Ce document d\ue9crit les caract\ue9ristiques d?acoustique et de milieu sonore de 27 salles de classe traditionnelles, de forme rectangulaire, parmi les 41 salles ayant \ue9t\ue9 mesur\ue9es. Le but de ces travaux \ue9tait de permettre de mieux comprendre comment am\ue9liorer la communication de la parole entre enseignants et \ue9l\ue8ves. L?\ue9tude a r\ue9v\ue9l\ue9 les valeurs moyennes suivantes, durant les classes, du point de vue des \ue9l\ue8ves : niveaux sonores de la parole \ue9mise par l?enseignant de 60,4 dBA, niveaux de bruit de 49,1 dB, et rapport signal vocal/bruit moyen de 11 dBA. Le temps de r\ue9verb\ue9ration moyen dans les salles de classe occup\ue9es \ue9tait de 0,41 s, soit 10 % de moins que dans les salles inoccup\ue9es. On a utilis\ue9 les mesures des temps de r\ue9verb\ue9ration pour d\ue9terminer la valeur d?absorption moyenne qu?ajoutait la pr\ue9sence de chaque \ue9l\ue8ve. Les analyses d\ue9taill\ue9es des sons conversationnels \ue0 arriv\ue9e imm\ue9diate et de ceux \ue0 arriv\ue9e tardive ont r\ue9v\ue9l\ue9 que ces niveaux sonores pouvaient \ueatre pr\ue9dits avec assez de pr\ue9cision. Ces analyses font entrevoir des approches am\ue9lior\ue9es au probl\ue8me de la conception de l?acoustique des salles.Peer reviewed: YesNRC publication: Ye