The impacts of room acoustic quality levels on speech intelligibility in open-plan offices: A laboratory study

Speech sound has often been considered as a source of interfering noise in previous studies examining the impacts of acoustic environments in open-plan offices. However, speech sound in open-plan offices is not always a source of annoyance; it can also be a useful speech signal that can benefit the work. A laboratory experiment was conducted to examine the impacts of room acoustic quality on speech intelligibility of useful speech signals in open-plan offices. Speech intelligibility score and subjective speech intelligibility and acoustic perceptions were tested at two receiving positions in four open-plan offices with different acoustic quality levels. The room acoustic quality of four open-plan offices was classified into four levels, from high to low, based on ISO 3382-3:2022 Annex C. The results indicated that open-plan offices with high or medium-high acoustic environmental quality can better meet speech intelligibility requirements within and between teams, according to the acoustical classification of ISO 3382-3:2022 Annex C. Practical Application This paper studies the effects of room acoustic quality levels in open-plan offices on speech intelligibility of useful speech signals and acoustic perceptions, and demonstrates the effectiveness of the acoustic classification in Annex C of ISO 3382-3:2022. When designing the acoustic environment of open-plan offices, the acoustic parameter values of medium-high or high acoustic quality that meet the acoustic classification in ISO 3382-3:2022 should be given priority as design goals, and the distance between team members should be arranged within 7 m as much as possible to ensure communication within the team and reduce potential interference between teams.