Well, you need one per floor, and one per bedroom ... /s

No, not really all that sarcastically, there are a lot of people who live that way, have the tv constantly on in the background. When I was still living at home, a friend (who always had the tv on, even when she had company over) came to visit me. After a while, she asked why my mom had the tv off in a tiny viewing area way off in an unsociable corner. I said that when my mom had company over, she wanted the focus to be on their conversation and interaction and friendship, not on the TV, and my friend found this to be an astonishing concept.