A:Answer HDMI 3 on the LG CX 65 inch Class 4K Smart OLED TV w/ AI ThinQ® (64.5'' Diag), Model # OLED65CXPUA is not an HDMI ARC port. It is an HDMI eARC port. To overcome the limitations of ARC, eARC (Enhanced Audio Return Channel), was developed and incorporated into HDMI ver 2.1 and the HDMI eARC port adds the ability to transfer immersive audio formats, such as Dolby Atmos, DTS:X, and 5.1/7.1 channel uncompressed PCM audio from HDMI-connected source devices, as well as all audio from Smart TV streaming apps. This means that on TVs with eARC, you can connect all audio and video sources to the TV. The audio from those sources can then be transferred from the TV to an eARC compatible home theater receiver via a single HDMI cable connection...^IFV