The musical use of real-time digital audio tools implies the need for simultaneous control of a large number of parameters to achieve the desired sonic results. Often it is also necessary to be able to navigate between certain parameter configurations in an easy and intuitive way, rather than to precisely define the evolution of the values for each parameter. Graphical interpolation systems (GIS) provide this level of control by allocating objects within a visual control space to sets of parameters that are to be controlled, and using a moving cursor to change the parameter values according to its current position within the control space. This paper describes Interpolator, a two-dimensional interpolation system for controlling digital signal processing (DSP) parameters in real time.