A:Answer Typically, on a TV there are two types of ports, inputs & outputs. Inputs are intended to bring video and audio 'IN' to the TV. Outputs are intended to take audio 'OUT' of the TV, in order to be sent to a sound bar or audio system. ARC is a technology that allows an HDMI to be an input or an output. So if you are connecting a sound bar through HDMI you would have to use HDMI 1 to get audio 'OUT' of the TV to the sound bar.