A laboratory study for assessing speech privacy in a simulated open-plan office

摘要

The aim of this study is to assess speech privacy in open-plan office using two recently introduced single-number quantities: the spatial decay rate of speech, DL_(2,S) [dB], and the A-weighted sound pressure level of speech at a distance of 4 m, L_(p,A,S,4 m) [dB]. Open-plan offices were modeled using a DL_(2,S) of 4, 8, and 12 dB, and L_(p,A,S,4 m) was changed in three steps, from 43 to 57 dB. Auditory experiments were conducted at three locations with source-receiver distances of 8, 16, and 24 m, while background noise level was fixed at 30 dBA. A total of 20 subjects were asked to rate the speech intelligibility and listening difficulty of 240 Korean sentences in such surroundings. The speech intelligibility scores were not affected by DL_(2,S) or L_(p,A,S,4 m) at a source-receiver distance of 8 m; however, listening difficulty ratings were significantly changed with increasing DL_(2,S) or L_(p,A,S,4 m) values. At other locations, the influences of DL_(2,S) or L_(p,A,S,4 m) on speech intelligibility and listening difficulty ratings were significant. It was also found that the speech intelligibility scores and listening difficulty ratings were considerably changed with increasing the distraction distance (r_D). Furthermore, listening difficulty is more sensitive to variations in DL_(2,S) or L_(p,A,S,4 m) than intelligibility scores for sound fields with high speech transmission performances.