I had this happen once, and it turned out not to be on my lot at all. I have no clue what type of lot you are playing, but in my case, it was a "city" style area (I can't remember what town). The house was built within a square or two of the edge, and the house next door was also built close to the edge of the lot with the lots against each other. I spent a great deal of time trying to figure out where the TV sound was coming from. I finally figured out that the TV was in the neighbor's house! It was in the room next to the room where I would hear it, and apparently the windows allows the sound to travel. I edited the other lot, deleted the TV, and the sound issue on my own lot went away. I don't know if you are in a similar situation, but it's something to consider before destroying everything (I was ready to do that, too). Good luck!
