When a house has more than a couple of TVs, how the video signal gets distributed around the property matters just as much as which TVs you buy. A video matrix is what allows any source — Sky box, Apple TV, a games console — to be sent to any screen in the house, controlled from a single system. The trouble is, matrices are sized in fixed inputs × outputs, and that number needs to match the actual scale of the house, not just be picked off a standard price list. A 4×4 matrix