I recently picked up myself a beauty of a 55 inch 4k TV, but the build in speakers are crap, nothing new though. I want to grab a sound bar, but I keep seeing the labels "4k sound bar" being thrown around. What does this mean and does it play into sound quality? Will I need a 4k supporting sound bar for a 4k TV? Or is this another one of those 'higher quality' marketing schemes? I won't be using the HDMI port, only optical. Thanks!