This paper aims to give an overview on four empirical studies which explored the impact of background speech on cognitive performance and subjectively perceived disturbance. Background speech is the most serious noise problem in shared-room and open-plan offices for employees who are supposed to do silent, concentrated work. Different measures of acoustic office optimization, as well as the outstanding role of the intelligibility of background speech for its disturbance impact, are empirically evaluated.
The article provides a synopsis describing the core empirical results of four of our empirical studies. A survey study among office employees (n = 659) explored the subjective importance of office acoustics. Three experimental studies (n1 = 20; n2 = 30; n3 = 24) evaluated the effects of reduced background speech level, play-back of partial maskers and reduced speech intelligibility on cognitive performance and subjective ratings.
Background speech is subjectively perceived as a severe problem, and the different noise abatement measures affect objective performance and subjective ratings differently. Speech intelligibility is – besides level – a key determinant for the acoustic optimization regarding these two dimensions.
Practitioners are encouraged to apply the findings and described measures when planning and/or evaluating open-plan offices.
It is concluded that different acoustically efficient measures need to be combined to minimize the negative effects of background speech on cognitive performance and subjectively perceived disturbance. The aspired set value for open-office concepts is the lowest possible sound level with a bad intelligibility of the background speech at the same time.
The synopsis of several empirical studies allows deriving comprehensive and well-founded information for practitioners involved in the evaluation and/or design of offices environments.
This article is a modified and extended version of an article published in German language: Schlittmeier, S.J. and Liebl, A. (2012), Akustik im Büro: Zur Störwirkung von Hintergrundsprache, Lärmbekämpfung, 4/2012, pp. 183-188.
Schlittmeier, S.J. and Liebl, A. (2015), "The effects of intelligible irrelevant background speech in offices – cognitive disturbance, annoyance, and solutions", Facilities, Vol. 33 No. 1/2, pp. 61-75. https://doi.org/10.1108/F-05-2013-0036
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