The principle of the active JMC scatterer

The principle of formulating the JMC method to produce secondary sources that function as active scatterers on a hypothetical scattering surface is established, to be applied, e.g., in concert halls. The examination is based on the modified JMC method, to ensure that the logic does not lead to the need of changing the primary sources. The actively reflecting plane serves as an example of the JMC formulation for the active scatterer. The solution for the actively reflecting plane works on the local control principle: each reflecting subarea needs information of the primary field only at that subarea. The solution can also apply to piecemeal planar surfaces and to smooth convex surfaces, approximately.