A golf ball including an inner core having a geometric center and a first outer surface, the inner core being formed from a first substantially homogenous rubber composition, and an outer core layer formed from a second substantially homogenous rubber composition, the outer core layer having a second outer surface. As an example two fluid dynamic bearings are provided spaced apart along a shaft, one of the bearings comprising a fluid dynamic bearing, the other comprising an air bearing. The tap sensing unit receives the shock waves to generate a moire signal. In particular, the present document relates to the implementation of loudness control in multimedia players.