India, Oct. 13 -- A cousin of mine bought a lovely new TV last year, then added a well-reviewed soundbar a few weeks later and spent the next weekend wondering why the movie nights sounded no better than before. The culprit was a single port and a single setting. If you are planning to buy a TV and a soundbar together, or one after the other, this is the part of the spec sheet that deserves more of your attention than the wattage figure on the box. Here is what to check, in plain language, so the two devices cooperate instead of just sharing a shelf.

Look at the back of your TV and you will find several HDMI sockets, but usually only one of them is labelled ARC or eARC. That is the one meant for sending audio from the TV to the soundbar....