Sound scattering by a Janus sphere type is considered. The sphere has two surface zones: a soft surface of zero acoustic impedance\nand a hard surface of infinite acoustic impedance. The zones are arranged such that axisymmetry of the sound field is preserved.\nThe equivalent sourcemethod is used to compute the sound field. It is shown that, by varying the sizes of the softand hard zones on\nthe sphere, a significant reduction can be achieved in the scattered acoustic power and upstreamdirectivity when the sphere is near\na free surface and its soft zone faces the incoming wave and vice versa for a hard ground. In both cases the size of the sphere�s hard\nzone is much larger than that of its soft zone.The boundary location between the two zones coincides with the location of a zero\npressure line of the incoming standing sound wave, thus masking the sphere within the sound field reflected by the free surface or\nthe hard ground. The reduction in the scattered acoustic power diminishes when the sphere is placed in free space. Variations of\nthe scattered acoustic power and directivity with the sound frequency are also given and discussed
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