This study investigated the effect of a spatial factor, the magnitude of interaural cross-correlation ͑IACC͒ function, on subjective responses to heavy-weight floor impact sounds. Heavy-weight impact sounds were generated by a heavy/soft impact source ͑impact ball͒ in real apartments, so that impact sound pressure levels ͑SPLs͒ ͑L Amax ͒ and IACC could be analyzed. Just noticeable differences ͑JNDs͒ of impact SPL and IACC were investigated through the use of impact ball sounds. JNDs were determined by the criteria of 75% correct answers by participants, and it was found that JNDs of impact SPL and IACC were around 1.5 dB and 0.12-0.13, respectively. In addition, the annoyance caused by an impact ball was evaluated by changes in these two parameters. The results show that annoyance increased with increasing impact SPL and with decreasing IACC; the contributions of the two parameters to the scale value of annoyance were 79.3% and 20.4%, respectively. This indicates that the effects of IACC should be considered for the evaluation of annoyance, and the subjective response to impact ball sounds can be improved by controlling IACC, as well as impact SPL.

No abstract

Field measurements of floor impact sounds at lowf requencies give poor repeatability due to spatial sampling problems. In this study,t he spatial distribution of heavy-weight impact sound pressure levels wasi nvestigated by field measurements using heavy/soft impact sources, which have been specified as as tandard heavy-weight impact source in 140-11. The results of the present study showed that the vertical and horizontal distribution of measured sound pressure levels showed asignificant room mode effect at lowfrequencies. Among the existing standards for measurement of aheavy-weight impact sound, KS F2810-2 and JISA1440-2 provide an appropriate estimation of the room average sound pressure levelfor bare slab and floating floor,with respect to alow bias error and 95% confidence interval. The guideline for measurement of aheavy-weight impact source wasrecently proposed in order to complement the limitations of KS F2810-2 and JISA1440-2, and it has been shown that the guideline appropriately performed in the test building and in living rooms of tested apartment buildings. PACS no. 43.50.Pn, 43.55.Rg ©S.Hirzel Verlag · EAA 761 ACTA ACUSTICA UNITED WITH ACUSTICA Yo o et el.:S patial variation of impact ball sounds Vol. 96 (2010)

No abstract

No abstract