Evaluating the mitigating effects of water sounds on multi-dimensional negative reactions due to secondary radiation noise

People exhibit a range of negative reactions to noise. However, previous study on masking secondary radiation noise focused on its impact on a single negative reaction, namely dissatisfaction. This is a gap in understanding the mechanisms that mitigate multi-dimensional negative reactions (MNR), which encompass various emotional responses to noise, including annoyance, dissatisfaction, and others. Therefore, this study selected four mutually independent critical reactions (subjective loudness, depression, discomfort, and dissatisfaction) and analyzed the masking effects of adding four types of water sounds (fountain, stream, water-drop, and waterfall sounds) on MNR caused by secondary radiation noise. Seventy-nine participants were presented with a series of combined sound samples before casting their votes of MNR in an auditory test booth. The results revealed that adding the four types of water sounds mitigated the MNR induced by secondary radiation noise. Among them, the water-drop sound was the most effective, while the waterfall sound was the least capable. The fountain sound was preferred over the stream sound for optimizing the MNR, focusing on subjective loudness, discomfort and dissatisfaction, which were caused by higher level of combined sound. Furthermore, as global A-weighted sound level (LAeq) increased from 55 to 65 dBA, the mean subjective loudness levels generally remained the highest. Beyond the subjective loudness, when global LAeq increased to 65 dBA, the mean depression level exceeded the mean discomfort level and mean dissatisfaction level when the fountain or water-drop sound was added, whereas the three mean levels remained approximately equal when the stream or waterfall sound was added.