Sound masking in office environments—Trade-off between masking effect and user acceptance

Abstract

Solving cognitive tasks is adversely affected by speech sound (Irrelevant Speech Effect). In particular, the interfering potential of speech sound is high in open-plan office environments. Sound masking is one of the most effective methods to reduce the disturbing speech sound by covering certain fractions of it with a masking signal. Since the most effective masking signals are subjectively perceived as annoying themselves, the goal of this work was to develop a masking signal which fulfills both, a good masking effect and a high user acceptance. To achieve this goal, qualitatively different masking signals with varying structural properties were developed. The efficacy of these signals was tested in a laboratory experiment using a cognitive task (serial recall). In addition, a subjective evaluation of the signals (loudness, annoyance, etc.) was carried out. In the second part of this work, a questionnaire was developed, which can be used to evaluate the acceptance and the subjectively assessed effectiveness of newly developed masking signals by their potential users. Using this questionnaire, the newly developed masking signals were evaluated by persons working in open-plan offices. Findings and implications for practical usage are presented.