Assessment of Indoor Acoustic Performance: Impact of Interior Materials on Classrooms in Higher Education Buildings

The acoustic quality of classrooms in higher education institutions is very important to support effective and efficient teaching and learning processes. Poor classroom acoustic conditions can cause communication disorders, such as difficulty hearing instructions and misunderstandings, thus disrupting the learning process. This study investigates how interior element materials (floors, walls, and ceilings) can affect the acoustic performance of classrooms. The case study took classrooms from six higher education institutions, namely Petra Christian University, Ciputra University, Wilwatikta College of the Arts, and 17 August 1945 University in Surabaya, as well as Satya Wacana Christian University in Salatiga and the Indonesian Institute of the Arts in Yogyakarta. This study used a quantitative method using I-Simpa (Integrated System for Indoor Acoustic Performance Assessment) software. I-Simpa can identify deficiencies in sound quality by measuring RT30 (reverberation time), C50 (clarity), and D50 (definition) of each existing classroom. Data were collected through acoustic measurements and students' perceptions regarding their experiences with classroom acoustics. The findings can reveal the use of inappropriate interior element materials, which can significantly reduce the clarity of sound in the teaching and learning process in the classroom. The results of the study are expected to provide optimal acoustic material solutions and the most strategic layout to improve sound distribution in the classroom. This study provides suggestions for acoustic material management based on innovation and technology, which will be useful for designing classroom interiors in higher education buildings in the future.