Spatial Distribution and Influencing Factors of Speech Intelligibility in Round-Table Conversation Scenarios

Round-table conversations, as common social environments, greatly depend on effective verbal communication to enrich the interactive experience. However, considerable variations in speech intelligibility (SI) occur among listeners at different positions under negative factors. This study employed numerical simulations, in situ measurements, and subjective listening tests to evaluate the main factors affecting SI, and quantified SI using the Speech Transmission Index (STI) and Speech Reception Threshold (SRT). The results demonstrate that SI varies with listener position, with the extent of these variations surpassing expectations. The listeners closer to the speaker have a significantly greater SI than those across the table, with STI variations reaching 0.55 in the free field and 0.23 (SRT variations up to 3.1 dB) in the actual room. Both speaker orientation and listener head orientation greatly influence SI distribution and its positional sensitivity. Furthermore, the overall STI among listeners decreases by no more than 0.2 for each increase in table diameter. Overall, the trend of the change in SI in the actual room is essentially consistent with those in the free field, but reflections improve SI for listeners in less favorable positions. These findings reveal SI distribution patterns in round-table scenarios, providing evidence and insights for future research.