A control device comprising: a first processor (15, 20) that processes a first audio signal of a first standard; a second processor (16, 22) that processes a second audio signal of a second standard; a mode selection switch; a mixing processor that supplies the first audio signal which is input to the first processor (15, 20), receives the first audio signal processed by the first processor (15, 20), receives the second audio signal processed by the second processor (16, 22), produces a mixed audio signal by adding the received first audio signal and the received second audio signal, and outputs the mixed audio signal; a first output switch unit that operates in a linked manner with the mode selection switch, the first output switch unit outputting the mixed audio signal which is output from the mixing processor to an external device and outputting the first audio signal processed by the first processor (15, 20) to the second processor (16, 22) when the mode selection switch indicates a first mode, and the first output switch unit outputting the mixed audio signal which is output from the mixing processor to the external device and to the second processor (16, 22) when the mode selection switch indicates a second mode; a second output switch unit that operates in a linked manner with the mode selection switch, the second output switch unit supplying the input first audio signal to the first processor (15, 20) when the mode selection switch indicates the first mode, and the second output switch unit being able to switch between whether or not the input first audio signal is to be supplied to the first processor (15, 20) when the mode selection switch indicates the second mode; and a display that displays at least one of a level of the first audio signal, an execution state of the first processor (15, 20), a switching state of the second output switch unit, a level of the second audio signal, and a level of the mixed audio signal, wherein the control device further comprises: a switch that selects between whether or not the process at the first processor(15, 20) is to be executed when the mode selection switch indicates the second mode, wherein the display displays the switching state of the second output switch unit to indicate that the input first audio signal is supplied to the first processor (15, 20) when the execution of the process at the first processor (15, 20) is selected, and displays the switching state of the second output switch unit to indicate that the input first audio signal bypasses the first processor (15, 20) when the execution of the process at the first processor (15, 20) is not selected. a first processor (15, 20) that processes a first audio signal of a first standard; a second processor (16, 22) that processes a second audio signal of a second standard; a mode selection switch; a mixing processor that supplies the first audio signal which is input to the first processor (15, 20), receives the first audio signal processed by the first processor (15, 20), receives the second audio signal processed by the second processor (16, 22), produces a mixed audio signal by adding the received first audio signal and the received second audio signal, and outputs the mixed audio signal; a first output switch unit that operates in a linked manner with the mode selection switch, the first output switch unit outputting the mixed audio signal which is output from the mixing processor to an external device and outputting the first audio signal processed by the first processor (15, 20) to the second processor (16, 22) when the mode selection switch indicates a first mode, and the first output switch unit outputting the mixed audio signal which is output from the mixing processor to the external device and to the second processor (16, 22) when the mode selection switch indicates a second mode; a second output switch unit that operates in a linked manner with the mode selection switch, the second output switch unit supplying the input first audio signal to the first processor (15, 20) when the mode selection switch indicates the first mode, and the second output switch unit being able to switch between whether or not the input first audio signal is to be supplied to the first processor (15, 20) when the mode selection switch indicates the second mode; and a display that displays at least one of a level of the first audio signal, an execution state of the first processor (15, 20), a switching state of the second output switch unit, a level of the second audio signal, and a level of the mixed audio signal, wherein a switch that selects between whether or not the process at the first processor(15, 20) is to be executed when the mode selection switch indicates the second mode, wherein the display displays the switching state of the second output switch unit to indicate that the input first audio signal is supplied to the first processor (15, 20) when the execution of the process at the first processor (15, 20) is selected, and displays the switching state of the second output switch unit to indicate that the input first audio signal bypasses the first processor (15, 20) when the execution of the process at the first processor (15, 20) is not selected.