Just noticeable difference of Lp,A,S,4m specified ISO 3382-3

Abstract

In this study, the sound environmental characteristics of open-plan office (OPO) were investigated, and human perception of the sound environment of OPO was also investigated in terms of the single number quantity (Lp,A,S,4m) specified in ISO 3382-3. Furthermore, a design guideline that can enhance sound environment of OPO in terms of speech-privacy and human perception has been proposed. The sound environment of two OPOs was measured and modeled by computer simulation and auditory evaluation was conducted by 37 subjects and the stimulus that the subjects heard was generated based on Lp,A,S,4m value. Just noticeable difference value of Lp,A,S,4m was evaluated based on the responses to willingness to work, annoyance, speech privacy, and adjectives describing OPO's sound environment in each stimulus. The subjects evaluated each sound environment for its expressions of adjectives, for instance, immersive, pleasant, comfortable. As a result, it was found that people response differently when the Lp,A,S,4m value changes about 3 dB(A) averagely and positive adjectives have a negative correlation with Lp,A,S,4m. It is believed that the outcome of this investigation could be utilized as basic information when we design the optimal OPO sound environment. In addition, it could be helpful for establishing the standard design criteria.