A radially vibrating horn is studied as a possible system for scaling up sonochemical reactors. The anisotropic behavior of this horn was demonstrated, as were strong correlations among the acoustic field, the acoustic streaming and the sonochemical reactivity. A comparison with the classic laboratory horn exhibits the benefits of the larger emitting surface of the radially vibrating horn for homogeneous reactions, but not for polymer degradation reactions or for heterogeneous liquid-liquid reactions. The experimental techniques used proved to be very useful in characterizing the sonochemical reactors.