The influence of source position and orientation on speech intelligibility in school environments

In school environments, the teacher's position can change during lessons. Consequently, also the directivity of the sound source (i.e., the teachers' head), as well as its position, can vary, for example when standing, sitting, walking, using blackboard or speaking directly to one receiver. If the directivity varies significantly so does the speech intelligibility and this may affect students' comprehension and interfere with lessons, especially in case of volumes with poor acoustics. In this study, an experimental STI measurement campaign was delivered in a classroom measuring the sound pressure levels in several fixed positions. Results clearly indicate how the source orientation and position affect the intelligibility of the speech at receivers' locations with sensible variations from one configuration to another.