  The existence of only a few bubbles could drastically reduce the acoustic
wave speed in a liquid. Wood's equation models the linear sound speed, while
the speed of an ideal shock waves is derived as a function of the pressure
ratio across the shock. The common finite amplitude waves lie, however, in
between these limits. We show that in a bubbly medium, the high frequency
components of finite amplitude waves are attenuated and dissipate quickly, but
a low frequency part remains. This wave is then transmitted by the collapse of
the bubbles and its speed decreases with increasing void fraction. We
demonstrate that the linear and the shock wave regimes can be smoothly
connected through a Mach number based on the collapse velocity of the bubbles.
