Improving Room Acoustics in open-plan Offices. Testing the Relationship of acoustical and visual Distraction at Workspaces with sound-masking Systems

Many workspaces in open-plan offices suffer from high noise levels and undesired transmissions of speech noise between the users. These are leading to increased distraction by irrelevant speech information. This acoustical overall situation has serious consequences for the working environment: concentration- and performance loss as well as impairments of mood and well-being. Surveys on disturbing sounds have proven that human language distracts much more than sounds that are generated by natural sources or technical devices. Especially in times of changing working structures, when flexible spaces promoting interaction gain an increasing importance, room acoustics have to ensure that all negative impairments caused by noise and speech sound are prevented. Different measures and concepts come into question for acoustical optimization: absorption, shielding and sound-masking. Absorption can be achieved by means of acoustically-effective ceilings, floorings or furniture although these singular measures are often not sufficient. Sophisticated sound-absorbing systems are in the market. To reduce disturbing speech information sufficiently, advanced sound-shielding measures between the working areas are required. To efficiently prevent speech-like noise an adaptive sound-masking system in combination with visually adapted shielding elements should be developed, tested and implemented for open-plan offices in the presented research. The studies have shown that the design of these absorbing and shielding elements is a relevant factor as any conformity between spatial design and sound helps to improve the user acceptance. It was further verified by tests that permanent movements in the peripheral field of vision of the test persons were perceived as distracting and annoying. Thus the sound-masking was placed outside the field of vision. In general the user acceptance of masking sounds was assessed more positively when combined with a visualisation (e.g. covering with „leaves“) compared to the variant without any covering. But the whole system has to be further developed.