A wireless audio output device includes a plurality of audio output units, first and second audio output units among the audio output units being set as first and second roles, respectively. The first role is to establish a multicast link with a source device, to receive one or more media packets from the source device on the multicast link, and to perform bidirectional communication with the source device. The second role is to join the multicast link, to receive the one or more media packets from the source device on the multicast link, to perform unidirectional communication with the source device, and to perform unidirectional and/or bidirectional communication with the first role. An extended packet time slot is divided and each of the first role and the second role transmits or receives one or more extended packets during the extended packet time slot.