A mixer system comprising: a first display and a second display; an operating portion provided with physical controls including a button, a rotary encoder and a slider; a mixing processor that is adapted to process inputted audio signals and to output the processed audio signals; and a mixer controller, said mixer controller comprising: a first display controller for causing the first display to display a first view showing a representation of an entire console having a plurality of controls for controlling parameters for signal processing in the mixing processor; means for storing category information indicating which category each of the controls included in said first view belongs to, said categories including a button, a rotary encoder and a slider; means for allowing a user to designate, by user operation, a partial area of the representation of the console shown in said first view; a second display controller for causing the second display to display a second view showing the designated partial area; an accepting device for accepting designation of any one of the controls included in the second view displayed by the second display, to be assigned to one of the physical controls on the operating portion; an assigning device for assigning a parameter corresponding to the control of which designation the accepting device has accepted, to the one of the physical controls (21 to 23) that corresponds to the category of the control of which the designation is accepted, based on the stored category information of the control of which the designation is accepted; and a parameter controller for causing the mixing processor to change a value of the parameter assigned to the physical control (21 to 23) by the assigning device, in accordance with an operation when the physical control (21 - 23) is operated. a first display and a second display; an operating portion provided with physical controls including a button, a rotary encoder and a slider; a mixing processor that is adapted to process inputted audio signals and to output the processed audio signals; and a mixer controller, said mixer controller comprising: a first display controller for causing the first display to display a first view showing a representation of an entire console having a plurality of controls for controlling parameters for signal processing in the mixing processor; means for storing category information indicating which category each of the controls included in said first view belongs to, said categories including a button, a rotary encoder and a slider; means for allowing a user to designate, by user operation, a partial area of the representation of the console shown in said first view; a second display controller for causing the second display to display a second view showing the designated partial area; an accepting device for accepting designation of any one of the controls included in the second view displayed by the second display, to be assigned to one of the physical controls on the operating portion; an assigning device for assigning a parameter corresponding to the control of which designation the accepting device has accepted, to the one of the physical controls (21 to 23) that corresponds to the category of the control of which the designation is accepted, based on the stored category information of the control of which the designation is accepted; and a parameter controller for causing the mixing processor to change a value of the parameter assigned to the physical control (21 to 23) by the assigning device, in accordance with an operation when the physical control (21 - 23) is operated. a first display controller for causing the first display to display a first view showing a representation of an entire console having a plurality of controls for controlling parameters for signal processing in the mixing processor; means for storing category information indicating which category each of the controls included in said first view belongs to, said categories including a button, a rotary encoder and a slider; means for allowing a user to designate, by user operation, a partial area of the representation of the console shown in said first view; a second display controller for causing the second display to display a second view showing the designated partial area; an accepting device for accepting designation of any one of the controls included in the second view displayed by the second display, to be assigned to one of the physical controls on the operating portion; an assigning device for assigning a parameter corresponding to the control of which designation the accepting device has accepted, to the one of the physical controls (21 to 23) that corresponds to the category of the control of which the designation is accepted, based on the stored category information of the control of which the designation is accepted; and a parameter controller for causing the mixing processor to change a value of the parameter assigned to the physical control (21 to 23) by the assigning device, in accordance with an operation when the physical control (21 - 23) is operated.