고무공 충격음의 최소인지한계

Abstract

Rubber balls are used to measure the low-frequency impact sound on reinforced concrete and wooden structured apartment buildings. Previous studies on rubber ball impact sound showed that the physical properties of a rubber ball cause its impact sound to be similar to real impacts such as jumping and running of children. The rubber ball was standardized in ISO 10140-5 and ISO 16283-2, and studies on the SNQ of rubber ball were conducted. In addition, a classification on rubber ball impact sound is needed for the evaluation and labelling of low-frequency impact sounds. In this study, a subjective evaluation on the just noticeable difference (JND) of rubber ball impact sound was conducted. The presented rubber ball impact sound was recorded from wooden and reinforced concrete structures in apartment buildings. The JND of rubber ball impact sound, in which 75 % of the subjects can distinguish the loudness difference of two kinds of presented sound, was 4.65 dB for the wooden structure and 4.67 dB for the reinforced structure. On average, the JND of the rubber ball impact sound was 4.66 dB. For considering the harmonization with the classification scheme of other noise sources such as service equipment and airborne sound insulation in ISO/PRF TS 19488, a difference of 4 dB between classes is reasonable.