To provide a multichannel audio reproducing system etc. having higher capability of device compatible and higher versatility among devices made by different manufacturers.

A transmitting device 100 of the multichannel audio reproducing system appends and superimposes a remote control code signal S1 to a sound signal of channels C4 and C5 transmitted by radio communications to generate a multiplexed signal, and converts it to a modulated signal by a predetermined digital modulation method for transmission. At a recipient, a sound signal and a remote control code signal are separated from a received signal. Using a control signal obtained from a decoded remote control code signal, the sound signal is operated and controlled. Consequently, the capability of device compatibility and versatility among devices made by different manufacturers can be improved, since the remote control code signal S1 used popularly as a control information is appended to the sound signal for transmission as it is. In addition, since a transmitting unit 10 is made in a removable fashion, the compatibility of the transmitting unit 10 can be improved.