Experimental study of the layout of sound absorption materials in a classroom

Abstract

The following work has the general objective of investigating the arrangement of sound absorption materials in classrooms, through the acoustic parameters obtained. Classrooms are designed to promote learning through oral communication and listening. Thus, one of the main physical properties that determine the success of this function is the acoustic quality of the classrooms. Speech intelligibility is one of the most relevant parameters and can be improved by minimizing noise and reducing reverberation. A tactic to reduce the reverberation of a room is to dampen sound waves, using absorbent materials such as: padded chairs, curtains, carpets and sound absorption panels (SAP). However, the influence of the positioning of the elements, mainly of the SAP, is little studied. To carry out the experiments on the positions with the SAP, we used the Laboratory of Applied Mechanics (LabMEC), located at UFG. Based on ISO 3382-2, 2 and 3 distinct points were selected for the sound source and receiver, respectively, 5 SAP amount settings and 3 SAP placements, resulting in an overall full factorial experiment with 4 factors. The tests were performed ranging from zero to four SAP, always in different positions. The data obtained were analyzed by the technique of analysis of variance (ANOVA), aiming to identify the most significant factors for the acoustic performance of the environment. Due to the effect of SAP on sound dampening, it is expected that the greater the number of plates, the better the acoustic parameters. In addition, the comparison of the layouts regarding the arrangement of the plates, will make it possible to elucidate which positions will improve the acoustic treatment in classrooms. In the end, through ANOVA it will be possible to conclude that the acoustic performance of a classroom can be improved considering other factors besides the number of SAP.