A control unit for a musical instrument having a keypad and/or touch pad areas for controlling a signal processing unit. The control unit is preferably formed in a thin and elastic layered structure whereby touching electrode surfaces of the structure generates a charge, voltage or capacitance that is subsequently processed. The control unit includes a surface element, whereby settings and values of the signal processing unit can be changed and controlled by a user applying physical contact to the surface element. A user control device is further coupled to the control unit, and is operable under at least two forms of operation, and wherein the user control device is configured to (1) select an acoustic parameters and (2) adjust the selected acoustic parameter.