Impact sound insulation: Transient power input from the rubber ball on locally reacting mass spring systems

For heavy impacts in buildings, impact sound insulation is measured using the rubber ball in terms of the fast time-weighted sound pressure level, $\textit{L}_p_,_F_m_a_x$. With knowledge of the transient power input from the rubber ball, $\textit{L}_p_,_F_m_a_x$ can be predicted using Transient Statistical Energy Analysis. For the rubber ball falling onto a concrete floor, this transient power can be calculated from the measured blocked force. However, this is not possible when there is a floating floor. As this is the practical situation, this paper concerns experimental work to investigate idealised floating floors using a force plate. This was a steel plate on different resilient materials to represent a locally-reacting mass-spring system. Results show two characteristic force time pulses from mass-spring systems, a single and double peak for low and high stiffness springs respectively. These measurements were then processed to calculate the transient power input from each mass-spring system, and $\textit{L}_p_,_F_m_a_x$ measurements were taken in a room below a concrete floor with and without these systems. In terms of the difference with and without the mass-spring system a clear relationship has been found between the measured transient power input and the difference in the measured $\textit{L}_p_,_F_m_a_x$ for high stiffness springs.