Assessing acoustical quality in university classrooms in Brazil: Measurements and simulations

Abstract

The acoustic quality of learning spaces, such as classrooms, is a worldwide issue. Some countries have regulations or guidelines for these environments, which does not happen properly in Brazil. Beyond the lack of nationwide research related to classroom acoustics, Brazil has two standards with a few information related to classroom acoustics. One of them was written in 1992, having a single demand concerning an appropriate reverberation time for conference rooms at the 500 Hz frequency, without detailed requirement, in contrast to other national guidelines. Another one, updated in 2020, recommends the sound pressure levels for indoor environments, having classrooms in its list. The aim of this study is to analyze the acoustic quality of two Brazilian classrooms over a public university in the south part of Brazil. Several impulse responses were taken within the learning environments and then processed in Matlab with the ITA ToolBox. The classrooms were also modeled into RAVEN and I-SIMPA software aiming to identify different sound absorption schemes to improve their speech intelligibility. The findings showed that the classrooms had a bad acoustic environment, with a measured reverberation time of approximately [Formula: see text]. However, the simulation suggested that implementing sound absorption strategies could reduce the reverberation effects by half, bringing it closer to optimal levels. The estimated costs for implementing sound absorbers were [Formula: see text] for Classroom 01 and [Formula: see text] for Classroom 02.