A simple model to predict the cognitive performance in distracting background speech

Background speech in open-plan offices causes frequently high distraction and dissatisfaction. Particularly the short-term memory is impaired by irrelevant speech sounds. A good acoustical design is required to achieve acceptable acoustical privacy in open-plan offices. In addition to sound absorbers and sound screens, sound masking is an efficient measure to control the background noise level and to mask disturbing speech sounds. The existing algorithmic approaches to estimate the performance impairment when people are subjected to irrelevant background speech require considerable computational effort. A simple model is presented to predict the short-term memory performance indistracting background speech. The results of various laboratory experiments with masked speech sounds at both, low and high speech intelligibility, were considered. The fitted model can be used to optimise the design of open-plan offices and to predict the effectiveness of a masking sound.