Array of infinitely long cylindrical scatterers with main axis parallel to the reflecting plane (ground) is considered that results in treating problem as two-dimensional. This array, referred to as sonic crystal, is placed in acoustic medium with physical parameters of air. The acoustical properties of the ground are described by the Delany-Bazley empirical relationships. The interactions of waves scattered by each cylinder and reflected from the ground can be analysed by the previously developed numerical methods based on the Green theorem with the Green's function adjusted to the presence of the locally reacting ground. The results are compared with the multiple scattering in free acoustic space. It is shown that the insertion loss depends on the distance between the array and the ground as well as on the impedance of the ground.
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