A first content output device (e.g., speaker) may include a communication interface, an output unit, and a processor. The first content output device, upon receiving a request, selectively transmits audio content to an external content output device (e.g., speaker) via two different networks. While the external content device is buffering the audio content received from the first content device via a first network, the devices are setting up for connection via a different second network. When the setting for connection between the device via the second network is completed, the first content output device switches to transmitting the audio content to the external content output device via the second network.