The Effects of Lighting on Perceptual Sound Quality in Subjective Listening Tests

In subjective listening tests, listening conditions can significantly affect the measured results. Although there are some established standards, quantitative specifications for lighting level are rarely disclosed. This raises a question: does the lighting environment affect the perceived sound quality? In some audio-related industries, it is even widely believed that a darker environment is more conducive to improving the subjective sound quality. However, this conclusion clearly lacks convincing experimental data support and a scientific theoretical basis. In this study, a series of listening tests on preference sound quality were conducted under different lighting environments. The analyses on overall rating, program material, and the dispersion of raw data were presented. The results provide evidence that there are no significant effects of lighting on perceived overall sound quality. However, the unexpected significant effects related to program material were observed in some experiments. Additionally, the dispersion of ratings could be affected by the lighting level. These effects may contribute to the common misconception that a dim listening environment can improve perceived sound quality. More information and guidance toward conducting accurate and valid listening tests can be provided by comprehensive understanding of these effects.