Investigating vibration-based methods of measuring impact noise insulation to improve reproducibility at low frequencies

Abstract

Standard impact noise insulation testing is based on measuring the average sound level in a reverberant field in order to estimate the incident and/or radiated sound power. While this method is straightforward, the variation under reproducibility conditions is significant, and a significant portion of the uncertainty is due to the complications of measuring the sound field in the receiving space. This variation is largest at low frequencies, where the effects of spatial variation and modes in the receiving room are well documented. Measuring the vibration on the surfaces of an assembly, or measuring the vibration propagation through an assembly, may provide another measure of the impact insulation of the assembly that is not affected by the sources of uncertainty associated with measuring the sound field in a room. This paper reports on the results of preliminary investigations on floor assemblies in situ while excited by impact sources and the comparison with conventional receiving room sound pressure measurements.