A discharge-servo curve control method and device for an electrical discharge machine enables multiple discharge-servo curves to be chosen during a machining process in real-time. Multiple speech recognition units with differing capabilities and therefore implementation costs are provided. The operation is controlled by software running in a low power microprocessor 16. The middle zone may stretch in a single direction, whereas the edge zones may stretch in a different single direction or in bi- or multi-axial directions. The system may further include at least one biological andor chemical filter disposed downstream of the cleaning head.