Ljudmaskering i kontorslandskap : En studie om optimering av ljudmaskeringssystem

Sammanfattning: This thesis contains a study of how sound masking systems can be implemented in existing open-plan offices in order to lower the speech intelligibility. The purpose is to investigate how to optimize the sound pressure level and frequency response for a sound masking system. The aim of the thesis is to produce recommendations regarding the optimum sound pressure level for a sound masking system using a pink noise. This study is initially based on a background study of the acoustical challenges in open-plan offices. Measurements of the background levels in an existing open-plan office are made to analyze the existent audio spectrum, in order to create a customized masking sound. Furthermore, a survey is made, where employees are being exposed to several masking sound environments and get to answer a questionnaire regarding their individual experience of each sound environment. In addition to the pink noise sound environments, a fan sound and a café sound are tested. A simulation is made in CATT-Acoustic to analyze the effect of a masking sound theoretically, in a model based on a small open-plan office. Due to the covid-19 pandemic the test group is limited, and the background levels are most likely underestimated, compared to normal conditions. The results show that the most preferred sound environment among the test group is the café sound. The simulations indicate that the implementation of sound masking has a positive effect on the speech transmission index and distraction distance in the model based on a small open-plan office.