Does background sound impact cognitive performance and relaxation states in enclosed office?

•Background noise in enclosed offices can be better regulated.•Sound type and pressure level independently impact subjective assessments.•Auditory working memory is impaired at 60 dBA sound pressure.•Sound type and pressure level interaction affect LF/HF heart rate ratio.•Optimizing office sound improves behavior and perception. An enclosed office is defined as an individual room with full-height walls, equipped with the necessary tools and amenities to facilitate highly concentrated, independent work. Unlike open-plan offices, enclosed offices provide a more sound-controlled environment, which can be crucial for optimizing working and resting conditions. This study employed a 4 (background sound type: Quasi-white noise, running water, classical music, Chinese classical instrumental music) × 3 (sound pressure level: 40 dBA, 50 dBA, 60 dBA) factorial design to examine the effects of background sound type and pressure level on cognitive performance and relaxation states within enclosed offices. The findings indicated that increasing background sound pressure level to 60 dBA significantly impairs auditory working memory task performance; however, no significant differences were observed in auditory backward recall task performance at pressure level below 60 dBA (40 dBA or 50 dBA). The effect of background sound type on auditory working memory tasks was not found to be significant. In terms of subjective evaluations, background sound type significantly influenced participants’ experience of emotional pleasantness and dominance—the sense of control or power. Notably, exposure to classical music (“Blue Danube”) as background sound resulted in higher levels of reported emotional pleasantness and dominance. Furthermore, varying background sound pressure level significantly affected participants’ emotional arousal levels, highlighting the role of sound pressure level as a key factor in regulating emotional responses. These experimental results provide novel insight into how the acoustic environment in enclosed offices influences human behavior and perception and offer practical implications for designing and optimizing such environments.