Comparisons between simulated and in-situ measured speech intelligibility based on (binaural) room impulse responses

This study systematically compares acoustic simulation and in-situ measurement in terms of speech transmission index (STI), speech intelligibility scores and relationship curves when considering (binaural) room impulse response and four general room conditions, namely, an office, a laboratory, a multimedia lecture hall and a semi-anechoic chamber. The results reveal that STI can be predicted accurately by acoustic simulation (using room acoustics software ODEON) when there is a good agreement between the virtual models and the real rooms and that different reverberation time (RT) and signal-to-noise ratio (SNR) may exert less significant influence on the simulated STI. However, subjective intelligibility may be overestimated when using acoustic simulation due to the head-related transfer function (HRTF) filter used, and the score bias may be minimal and difficult to detect in everyday situations. There is no obvious score tendency caused by different RT, though with the decrease in the SNR, score bias may increase. Overall, considering that the accurate acoustic modelling of rooms is often problematic, it is difficult to obtain accurate speech intelligibility prediction results using a simulation technique, especially when the room has not yet been built.