In this paper some typical characteristics of the impact force when dropping a standardized rubber ball, as found in literature, are discussed. In addition, a simplified force function is proposed. The acoustic response due to dropping a standardized rubber ball is calculated by means of a convolution of a measured impulse response function and the impact force functions. The approach is applied to a floor to reconstruct the acoustic response in the receiving room, using time domain data of the impact force (as measured by Hopkins et al. [7]) and those obtained by a simplified force function. The results are compared with each other as well as with a directly measured acoustic response of the floor system.