Frequency Band Averaged Data for Prediction of Structure-borne Sound Power from Mechanical Installations in Buildings

Structure-borne sound transmission is a more complicated process than airborne sound transmission, but practitioners seek methods of prediction for the former, which are as straightforward as for the latter. In this paper a description is given of measurement and calculation procedures where the source activity (the velocity of the source when resiliently supported) and the mobility, and receiver mobility are measured and assembled as third octave values. As a further step in data reduction, single values of free velocity, source mobility and receiver mobility are measured directly, or indirectly using the reception plate method (RPM). Comparisons are made between measured source powers into a selection of plate-like receiver structures and RPM estimates. The findings point to the limitations of simplified methods, specifically the uncertainties likely as a result of reducing the measurement and computational effort.