Abstract: A system for interactively controlling multiple parameters affecting an audio output, the system employing a controller with a visual display (e.g., a cathode ray tube) for displaying an icon that is a visual representation of an input sound signal in a multidimensional space and an input device (e.g., a mouse) used to control the location of the icon on the display. The controller generates a multiple parameter control signal that is based upon the location of the icon and is used by a sound signal processing circuit to control multiple parameters affecting an audio output. The icons are images of the sources of sound input signals. The sound signal processing circuit has M times N controllable amplifiers arranged in an M by N matrix in which each of the M inputs is distributed to N controllable amplifiers and the outputs of M controllable amplifiers are combined to provide each of the N outputs.