Evaluating the effects of reverberation on speech intelligibility and head movement using spatial room impulse responses

Listeners must consistently distinguish between voices from different locations and cope with room acoustic effects in everyday listening. To evaluate how listeners cope with such conditions, three acoustic conditions: anechoic, classroom (reverberation time = 0.6 s), and auditorium (reverberation time = 1.3 s) each with two receiver positions, three target-masker separation angles: co-located, 45, and 90, and two target locations: to the front and to the side of the listener, were tested. 36 functionally monolingual American English listeners transcribed English sentences under different conditions reproduced using third-order spherical harmonics from spatial room impulse response measurements. Speech intelligibility scores and head movement were measured. Both the target and masker were female voices. Results show that speech intelligibility is significantly influenced by the room acoustic condition, target-masker separation, and target location. Speech intelligibility decreased with increasing reverberation and smaller target-masker separation. Interestingly, speech intelligibility was significantly higher for target locations that are not to the front of the listener. For head movement, main effects of the acoustic condition and target location were seen, with participants generally having more head movement for more difficult listening conditions. This study highlights the importance of implementing realistic acoustic conditions to better understand and capture how listeners cope in real-world scenarios.