Speech intelligibility in halls with Reverberation Enhancement Systems

Speech intelligibility is one of the most important aspects of room acoustics and is commonly evaluated in relation to objective parameters such as Reverberation Time (RT), Early Decay Time (EDT), and Clarity for speech (C50). As Reverberation Enhancement Systems (RES) become more popular, the aim of this research is to investigate objective and subjective speech perception in rooms equipped with such a system. As Reverberation Enhancement Systems (RES) become more popular, the aim of this research is to investigate objective and subjective speech perception in rooms equipped with such a system. Objective parameters of room acoustics: RT, EDT, C50 and STI (Speech Transmission Index) were measured in four RES-equipped rooms. Additionally, a listening test involving 240 subjects with normal hearing was performed to assess the subjective intelligibility with the Logatome Intelligibility (LI) index. Speech stimuli convolved with a room impulse response were presented to listeners. Comparing objective (STI) and subjective (LI) intelligibility results with objective parameters of room acoustics revealed some differences compared to rooms without RES. Intelligibility in RES-equipped interiors exhibited a smaller decrease in LI with increasing RT, which might be caused by nonlinear decrement of reverberation. These findings suggest the possibility of designing spaces with extended RTs without sacrificing speech clarity and, consequently, intelligibility. The results contribute to the ongoing discourse on the relationship between objective metrics and subjective evaluations of room acoustics for speech intelligibility.