Analysis of intelligibility and reverberation time recommendations in educational rooms

Acoustic parameters, including background-noise levels, reverberation time and intelligibility, were analyzed in 17 auditoria and multi-purpose conference rooms at the University of Extremadura. The study of intelligibility was performed by measuring the objective parameters and by using speech tests to study the subjective responses of listeners (speech intelligibility). Relationships between objective and subjective intelligibility parameters were studied, and the grouping of the experimental data was considered to reduce variability. It was concluded that the STI value is a good predictor of the intelligibility of rooms. Relationships between STI values with background-noise levels and reverberation time were also studied.Different proposals of recommended reverberation time were analyzed, taking into consideration the STI values of the studied rooms. Improvements in the slopes of the recommended equations were suggested.