Three-dimensional virtual reality-based subjective evaluation of road traffic noise heard in urban high-rise residential buildings

In this study, a new noise evaluation method is proposed in which virtual reality (VR) technology in the form of a head-related transfer function (HRTF) and a head-mounted display (HMD) is applied to assess the noise experienced inside residential buildings. Firstly, the sound pressure level and frequency characteristics of road traffic noise recorded in a living room were identified before and after applying the HRTF. Secondly, the subjective response was evaluated in terms of loudness, annoyance, disturbance, and allowance for road traffic noise levels L-Aeq of 40-65 dB in four different test environments, namely, without the HRTF or HMD, with the HRTF, with the HMD, and with both the HRTF and HMD. The impacts of the directional information provided by the HRTF and the visual information provided by the HMD were 77% and 23%, respectively. Furthermore, based on an evaluation of the source- and environment-related spatial attributes, the recognition of road traffic noise was the highest with the HRTF, and the recognition of space was the highest with the HMD. When both the HRTF and HMD were applied, the influence of sound externalization in the VR environment increased along with the sense of immersion and realism. Moreover, the recognition of the noise direction and noise width played a significant role in the psycho-acoustic impact, including the annoyance level of the road traffic noise. The findings of this study provide new insights on the influence of external noise on indoor environments.