An audio output apparatus which outputs an audio signal to an audio control apparatus controlling processing of the audio signal, and to which an external device having an external terminal is connectable includes an output terminal, a detecting section, a generating section, and a transmitting section. The output terminal is connected with the external terminal and outputs the audio signal to the external device via the external terminal. The detecting section detects whether or not the external terminal is connected to the output terminal. The generating section generates a control signal based on a result of the detection by the detecting means. The transmitting section transmits the generated control signal to the audio control apparatus in order that the audio control apparatus controls the processing of the audio signal based on the control signal.