Changes to the functionality and the detection and an expansion of a signal processing apparatus that processes an input signal are disclosed. A first signal processing means processes the input signal, and an expansion means adds a second signal processing means. A detecting means detects whether the one or more additional second signal processing means has been added on to the expansion means, a communication means for performing data transfers between the first signal processing means and second additional signal processing means via wireless communication, and a control means for coordinating the first signal processing means and the one or more additional signal processing means. The input signal is processed in accordance with a combination of the function of the first signal processing means, the respective functions of the one or more additional signal processing means, and the coordination of the first signal processing means and the one or more additional signal processing means.