Hybrid active noise barrier with sound masking in open-plan offices

This paper presents a small-typed active noise barrier (ANB) with sound masking techniques for alleviating the noise problem and protecting the speech privacy in open-plan offices. This soundproof system reduces and masks the undesired sound simultaneously so that lower level of the masker is required to achieve the sound masking effect, comparing with the conventional sound masking systems. First, a real-time experiment to verify the noise attenuation performance of the proposed system for practical application has been conducted in a real office room. In the experiment, the influence of background noise on the system performance has also been investigated. The experiment results show that 3-8 dB active noise attenuation can be achieved behind the ANB in an office room. Moreover, in order to select an appropriate masker for the sound masking part of the system, several maskers have been compared and investigated by listening experiments. The results suggest that the stationary maskers are more suitable for the sound masking in offices by considering the sound masking performance and the annoyance of the maskers comprehensively.