Originally Posted by FirstLady
I apologize for my inexperience. Which two pieces of equipment are connected by the optical cable? The tv and cable box. Or the tv and the htib unit. Also what is CEC?
First things first, when using a cable set top box, the audio should run direct to the theater receiver. It should not run through the TV. Your system has two HDMI inputs. So, connect the cable box to one of the inputs. Your receiver will process the audio and send the video out to the TV. ARC will not be involved.
You only need to feed audio from the TV to the sound system for sources that come from the TV. If you had an off air antenna instead of a cable box, you'd need to feed audio from the TV to the receiver. Or, if your TV has access to streaming sources such as Netflix, then you'd need to feed audio from the TV to the receiver.
There are two ways to get audio from a TV to a sound system. The older way (and still better/simpler, in most cases) is to run an optical audio cable from the TV's output to an available optical input on the receiver. The other way is to use the same HDMI cable that feeds the signal from the AVR to the TV. ARC (Audio Return Channel) is a feature of the latest version of HDMI used to feed audio back from the TV to the receiver. It requires ARC support on both the TV and the AVR. And you have to do the CEC (Consumer Electronics Control) setups on both devices. CEC allows one HDMI device to run another. But, it can be a pain to configure and it often has unintended consequences, which is why I say using an optical connection from the TV to the AVR is simpler.
However, unless you have audio sources that originate in the TV and cannot be run directly to the AVR, there's no reason to bother with ARC or a separate optical connection. Just run all your devices to the AVR and a single HDMI from the AVR to the TV for video. Another reason to go that route is that most TVs only output stereo, not 5.1, from devices attached using HDMI. So, a DD 5.1 track on a TV show would end up stereo coming through the TV.