All TCL TVs come with HDMI ARC disabled by default. To enable HDMI ARC, follow these steps: Open the “main screen” by pressing “ Home ” on your remote > Scroll up or down and select “ Settings ”. After that, scroll down and select “ System” > Scroll down and select “ Control other devices (CEC)”. Select “HDMI ARC” by The LG used to work flawlessly with a Sony BDV-E380 Blu-Ray Amp using HDMI CEC (Consumer Electronics Control) and ARC (Audio Return Channel), but the Denon - LG connection is problematic. I was able to get the LG and Denon communicating via HDMI CEC and ARC working at one time (msyteriously), but then I had to do some maintenance behind the TV You may want to start by taking a look at the information in: Control your TV or receiver with your Siri Remote or Apple TV Remote. Specifically the section titled "Make sure that HDMI-CEC is on" at the bottom of the article. We appreciate you reaching out to Apple Support Communities. vIieom.