Combined effects of sound and illuminance on indoor environmental perception

Cross-modal effects of sound and illuminance were investigated in an indoor environmental chamber with 60 university students (30 men and 30 women) aged 18-26 years. A within-subject factorial design was employed with four independent variables: noise level (45, 55, 65, and 75 dBA), noise type (Music, Water, Babble, and Fan), illuminance level (150, 500, and 1000 lx), and sex (female or male). The test conditions represented daily indoor environments, which was moderately noisy and did not present severe lighting conditions. Acoustic (loudness, annoyance, pleasantness, and naturalness) and visual (brightness and relaxation) semantic attributes were assessed using an 11-point numeric scale. The illuminance level of the ambient lighting system did not affect acoustic perception. Brightness was not altered by sound, but relaxation was affected by sound. Cross-modal interactions were asymmetric between sound and illuminance in indoor environmental settings. Women were more sensitive to the perception of both acoustic and illuminance stimuli than men, at high level of stimulation.