Comparing impact insulation measured with the rubber ball versus the tapping machine

ASTM test methods for measuring impact noise insulation use a standard tapping machine, which generates impact noise by dropping steel hammers on the floor surface. An alternative source is the heavy/soft impact source or rubber ball, which is defined in ISO 10140. The heavy/soft source was developed in Japan to correlate with sources such as walking without shoes and children jumping. Compared to the tapping machine, it generates elevated noise levels at low frequencies and generally negligible noise above about 500 Hz. The relationship between low frequency impact noise insulation measured with the tapping machine, such as LIIC, and with the heavy/soft source has not been well characterized for assemblies that are common in North America. The authors present field and laboratory data of impact insulation with both sources, and analyze the data to describe the relationship between the sources and what information they provide to the designers of floor assemblies.