Passive variable acoustic technology for classroom reverberation time: a case study

Abstract

PurposeTo maximise acoustic comfort in a classroom, the acoustic conditions of the space should be variable. So, the optimal acoustic state also changes when the classroom changes from a study environment into a lecture environment. Passive Variable Acoustic Technology (PVAT) alters a room’s Reverberation Time (RT) by changing the total sound absorption in a room. The purpose of this paper is to evaluate the improvements to classroom acoustic comfort when using PVAT.Design/methodology/approachThe study is conducted in an existing tertiary classroom at Auckland University of Technology, New Zealand. The PVAT is prototyped, and the RTs are measured according to international standards before and after classroom installation. The acoustic measurement method used is a cost-effective application tool where pre- and post-conditions are of primary concern.FindingsPVAT is found to offer statistically significant improvements in RT, but the key benefits are realised in its’ ability to vary RT for different classroom situations. It is predicted that the RT recommendations for two room types outlined in the acoustic standard AS/NZS 2107:2016 are satisfied when using PVAT in a single classroom space. By optimising RT, the acoustic comfort during both study and lecture is significantly improved.Originality/valueWhen PVAT is combined with an intelligent system – Intelligent Passive Room Acoustic Technology (IPRAT) – it can detect sound waves in real time to identify the optimal RT. This paper details a pilot case study that works towards quantifying the benefits of IPRAT, by prototyping and testing the PVAT component of the system.Highlights A pilot case study outlines the development and test of a variable acoustic prototype in a tertiary classroomA method is adopted to measure acoustic conditions, using three under-researched Android applicationsThe benefits of PVAT are realised in its ability to vary RT by adjusting the prototypes’ sound absorptionBy using PVAT in a single space, the recommended RTs for two room types outlined in the acoustic standard AS/NZS 2107:2016 can be satisfiedThe improvements in acoustic comfort due to PVAT are statistically significant