Excessive reverberation time in classrooms can impair speech intelligibility, reduce lecture quality, and hinder students' listening efficiency. Implementing precise and scientifically rigorous acoustic modifications is crucial for these classrooms. Calculations and simulations based on Sabine's equation or acoustic modeling software require precise absorption coefficients of the finishing materials, making it challenging to determine the required sound absorption increment. This paper proposes a method of equivalent substitution measurement: A non-destructive control group is established for acoustic experimentation, allowing for the precise calculation of the sound absorption increment required to achieve the target reverberation time. This approach provides scientific, rigorous, and customized reverberation time recommendations particularly for complexly shaped spaces from small to medium size to optimize the acoustic environment.

Acoustic performance is an important component of interior environmental quality, yet conventional single-value reverberation time metrics may provide limited perceptual information because they do not explicitly account for the spectral energy distribution of the evaluated sound. This study proposes an energy-weighted single-value reverberation time metric, Tew, which integrates frequency-dependent reverberation time with the relative contribution of received sound energy across frequency bands, providing a sound energy metric for building-acoustic assessment. Tew was evaluated using measured room-acoustic data under controlled laboratory conditions and in eight practical rooms, followed by a listening experiment involving 100 participants. Regression analyses and linear mixed-effects models showed that Tew was positively associated with perceived reverberance. Tew showed greater explanatory power and a better model fit than Tmf, whereas its performance was comparable to Tavg. The energy-weighting principle was further applied in a practical room-renovation project to identify frequency-dependent acoustic deficiencies and guide targeted acoustic treatment. The results demonstrate the potential of Tew to provide additional perceptually relevant information for assessing acoustic performance in interior spaces and to support frequency-aware acoustic treatment decisions. The practical renovation case further demonstrates the feasibility of integrating Tew and its underlying energy-weighting principle into building-acoustic assessment and treatment workflows, providing a link between sound-source characteristics, room-acoustic diagnosis, and targeted acoustic intervention.

Reverberation time is a key parameter for room acoustic evaluation in building commissioning and renovation. However, on-site measurements are often affected by background noise and limited speaker power, leading to unstable or unreliable results. Based on international standard ISO 3382-2:2008, this study compares the interrupted noise and exponential sine sweep methods and proposes an optimized measurement and data processing strategy that combines the respective advantages under non-ideal conditions. Experiments were conducted in six representative rooms at the University of Pécs, using both conventional and optimized approaches. The proposed method significantly reduces the dispersion of measured reverberation times across octave bands, leading to more consistent and reliable results under practical measurement conditions.