Hello, looking to replace my 15 yr-old TV. I’m considering the Sony Bravia XR55X90CJ from Costco. Looking at the specs, the audio output from this TV is 2 channel only. I have a Vizio 5.1 soundbar with inputs: optical, stereo audio, and HDMI. What would I need to do to get 5.1 audio from this TV to the soundbar? Doesn't Dolby Audio provide 5.1 channels? Thanks.