Background Noise, Noise Sensitivity, and Attitudes towards Neighbours, and a Subjective Experiment Using a Rubber Ball Impact Sound

When children run and jump or adults walk indoors, the impact sounds conveyed to neighbouring households have relatively high energy in low-frequency bands. The experience of and response to low-frequency floor impact sounds can differ depending on factors such as the duration of exposure, the listener’s noise sensitivity, and the level of background noise in housing complexes. In order to study responses to actual floor impact sounds, it is necessary to investigate how the response is affected by changes in the background noise and differences in the response when focusing on other tasks. In this study, the author presented subjects with a rubber ball impact sound recorded from different apartment buildings and housings and investigated the subjects’ responses to varying levels of background noise and when they were assigned tasks to change their level of attention on the presented sound. The subjects’ noise sensitivity and response to their neighbours were also compared. The results of the subjective experiment showed differences in the subjective responses depending on the level of background noise, and high intensity rubber ball impact sounds were associated with larger subjective responses. In addition, when subjects were performing a task like browsing the internet, they attended less to the rubber ball impact sound, showing a less sensitive response to the same intensity of impact sound. The responses of the group with high noise sensitivity showed an even steeper response curve with the same change in impact sound intensity. The group with less positive opinions of their neighbours showed larger changes in their subjective response, resulting in the expression of stronger opinions even to the same change in loudness of the impact sound. It was found that subjective responses were different when subjects were performing activities of daily living, such as reading or watching TV in the evening, and when they were focused on floor impact sounds in the middle of the night.