Audio apparatus and method for transmitting audio signal and audio system

PURPOSE: An audio device, an audio signal transmitting method thereof, and an audio system are provided to process the audio signal wirelessly received from an external device and to wirelessly transmit the processed audio signal to the other external device. CONSTITUTION: A wireless transceiver(121) wirelessly receives the audio signal from the first external instrument. An audio signal processing(122) converts the received audio signal into the audio signal of the multichannel. A controller(127) wirelessly transmits the audio signal of one channel among the audio signals of multichannel to one or more second external devices. An audio output device(123) outputs the audio signal of the channel of one except at least one channel.