Speaker
Description
Acoustic conditions in naturally ventilated classrooms are influenced by open windows, ceiling-fan operation, and external noise sources. The resulting spatial heterogeneity cannot be adequately captured by conventional single-point measurements or energy-averaged acoustic metrics. This limitation constrains the ability to assess and design for speech intelligibility in real-world educational environments. Our study examines speech intelligibility across classroom spaces under typical operating conditions during summer.The study was conducted in a secondary school classroom in Roorkee, India. Word recognition test was administered to students seated across multiple spatial zones under baseline conditions (fan on, windows and doors open). Concurrent acoustic measurements (LAeq, L90) were collated and RT60; SNR and STIPA computed across the classroom. The results indicate marked seat-wise variation in perceived speech intelligibility. The observed patterns suggest that proximity to openings and external noise sources may influence word-recognition performance. Temporal variation between morning and afternoon sessions and linguistic variation between Hindi and English word tests were also examined. Overall, the acoustic environment allowed speech to remain generally audible, but word-level intelligibility varied across classroom locations.The study foregrounds spatial variability as a critical dimension of classroom acoustics. It proposes a field-based protocol for evaluating speech intelligibility in naturally ventilated classrooms.