Acoustic wave propagation in liquid media containing many parallel air-filled cylinders is considered. A self-consistent method is used to compute rigorously the propagation, incorporating ail orders of multiple scattering. It is shown that, under proper conditions, multiple scattering leads to a peculiar phase transition in the acoustic propagation. When the phase transition occurs, a collective behavior of the cylinders appears and the acoustic waves are confined in a region of space in the neighborhood of the transmission source. A novel phase diagram is used to illustrate the distinct phase states in the acoustic propagation.
