During the renovation of our living room, one of the things I found important was hanging the TV, without cables and cupboards. I also wanted the soundbar under the TV to hang tight against the TV.
To determine the height of the TV, I used the seating position on the sofa and measured how high my eyes are then. I then divided the height of the TV into three pieces and made sure that my eyes are at 1/3 of the top of the TV.
Once I determined the position on the wall, I was able to calculate where the wall bracket would be. With a small margin above that, I drilled the boxes for the connections. Because all the pipes run through the ceiling to the meter cupboard, I have no problem when drilling the holes of the wall bracket.
Incidentally, I chose five built-in boxes; three wall sockets for power, 1 CAI connection and a double UTP connection.
I now use that double UTP for network for the TV and the Sonos Playbar, but possibly I could replace one for HDMI via UTP.
Because I have Ziggo as a provider, I can use a CI + module in the TV, with a smart card. Therefore I do not need a decoder to decode a digital TV signal. As a result, I do not need a TV cabinet or cables and it looks sleek.