Exploring Factors Influencing Speech Intelligibility in Airport Terminal Pier-Style Departure Lounges

This study investigates speech intelligibility and its influencing factors within pier-style airport lounges and assesses the applicability of the Speech Transmission Index (STI) in these large, elongated spaces. Field impulse response measurements were conducted in two pier-style departure lounges with volumes of 98,099 m3 and 60,414 m3, respectively, complemented by simulated binaural room impulse responses for subjective speech intelligibility testing in Mandarin. The research explores the correlations between various acoustic parameters—Early Decay Time (EDT), Reverberation Time (T30), and Definition(D50)—and speech intelligibility scores under different Signal-to-Noise Ratios (SNRs). Findings indicate a significant impact of SNR on speech intelligibility, with a coefficient of determination (R2) of 0.849, suggesting substantial variability explained by SNR. As SNR increases to 10 dB(A), speech intelligibility scores improve significantly; however, further enhancements in clarity diminish beyond this threshold. Additionally, the study reveals a significant relationship between room acoustic parameters, particularly EDT and D50, and speech intelligibility scores, with EDT having a negative impact and D50 a positive impact on speech clarity. The results confirm the suitability of STI in evaluating speech intelligibility in these specific architectural contexts. This study recommends maintaining an SNR of 10 dB(A) and a minimum STI of 0.45 for public address broadcasts in pier-style departure lounges to ensure that announcements are clearly audible to passengers.