Impact Sound Insulation: The Standard Tapping Machine Shall Learn to Walk!

Abstract

Previous research on the standard tapping machine has shown that the impact on a floor depends strongly on the combined system of floor and tapping hammers. This means that in general, a particular measure to reduce the impact sound pressure level can be advantageous with one impact source and disadvantageous with another. Conversion from one impact source to another has to be made for each floor individually, provided there is a sufficient knowledge of the dynamic properties of the source and floor. So, if the standard tapping machine is to be used to characterise a floor with respect to walking noise, the only simple way out of the problem is to make it ‘behave like a walker’. That means it should have the same source impedance. Investigations at the Fraunhofer-Institut für Bauphysik Stuttgart showed that this could be achieved by small modifications to the standard tapping machine. Comparisons using a concrete floor and a wooden joist floor have proved that results using such a modified tapping machine are much closer to walking noise than the results using the standard tapping machine.