hi, I've just bought a LG sound bar to connect to my Sony KD-55x8005C tv. I've tried to connect it via hdmi/arc and changed the TV settings to pick up the sound bar rather than the TV speakers, but I get no sound. TV gives me a message to say it's connected to the sound bar but as mentioned no sound. I can connect and play music from my phone to the sound bar via Bluetooth so I think the sound bar is ok. 

Any ideas? Do I have to use the optical input connection instead?

thanks, and sorry if this is a silly question, I am no expert.