The effects of masking sound and signal-to-noise ratio on work performance in Chinese open-plan offices

Abstract

A laboratory experiment has been carried out in this paper to study the effects of masking sound and signal-to-noise ratio (SNR) on occupants’ objective performance and perceived sound environmental quality in Chinese open-plan offices. The serial recall task performance and subject perceptions of 30 participants were tested under 14 different acoustic conditions, including “Quiet” (the condition without neither masking sound nor speech noise), “Speech_only” (the condition without masking sound but with speech noise), and 12 masking sound conditions. In these masking sound conditions, 4 masking sources (speech-like pink noise, air-conditioning noise, spring water sound and babble) were used and each source was given under 3 levels of SNR (i.e., small (−6.6 to −5.5 dB), medium (−3.0 to −2.3 dB) and large (4.4–4.8 dB) levels). The results demonstrate: (1) the effects of masking sound environment on occupants’ objective performance and perceived sound environmental quality (including acoustic satisfaction, perceived disturbance and subjective workload) can significantly differ by masking source and SNR, (2) spring water sound at medium SNR (SNR = −2.4 dB) is the best condition among the tested 12 masking sound environments, and (3) the effects of masking sound on occupants may differ by their individual factors, such as gender, educational level and noise sensitivity. According to the authors’ knowledge, this study is the first attempt to study the effects of masking sound and SNR on work performance in Chinese-language open-plan office environments. The findings can be used as a reference for the acoustic research and design of Chinese open-plan offices.