Investigation of vibration-based measurements of impact and airborne noise insulation

Abstract

Standard impact and airborne 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 attempt to reduce the uncertainty has so far proven unsuccessful. It is possible that a significant portion of the uncertainty is due to unavoidable variation in reverberation rooms, and that measuring the vibration on the surfaces of an assembly may be a better measurement of the impact or airborne isolation of the assembly. Preliminary investigations have been performed by measuring the vibration levels on wall and floor assemblies in situ while excited by airborne and impact sources, and the results are compared to conventional test methods.