For reasons we know about (I'll write it shortly) the only time you can pass through more than stereo is on Over The Air content. That is, stuff that comes over the antenna input.
Why is this? HDMI mandates HDCP and one of the HDCP rules the industry adhers to is that if a device can display a signal, then it must only pass Standard Definition (SD). KEEP READING. When it comes to audio, if the device can make sound, then the pass must be STEREO.
These are the industry rules. HDMI is not consumer friendly. It's that simple.
To get real surround sound the industry rules means that if you want 5.1 sound (or better than stereo) you run the HDMI to your sound system then either HDMI to the HDTV or optical to the sound system and HDMI to the HDTV.
It's all very simple when you know about HDMI and HDCP rules.
Bob
I have a Samsung 55" Smart TV, Model #UN55ES6150F, and recently bought a Vizio Sound Bar, Model .#VHT-510-B. They work with my Direct TV and the HD DVR.
The problem is the rear Vizio speakers that are wired into the rear wireless sub-woofer will not work. The sub-woofer works great as does the rest of the sound bar. Vizio says the rear speakers will only work with Dobly Digital sound. When I go to the SPDIF output setting in the sound mode of the TV it shows the TV in PCM mode. It shows Dobly Digital and DTS modes both "grayed out" and will not allow me to change modes.
Samsung techs state the TV must receive a Dobly Digital signal before you can change modes. My Direct TV receiver is set to Dobly Digital and the receiver is connected to the TV with an optical cable.
Samsung says the TV will only receive Dobly Digital signals from programs like Netflix or other streaming programs. This does not seem right.
Any help in getting the TV settings changed would be greatly appreciated.
Vizio and Samsung are blaming each other! Surprise!
Thanks.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic