A:AnswerUm........ Depends on the TV. If it has Bluetooth then you should buy the bluetooth version of these headphones. Then you wouldn't need to plug them in. This version is wired only so yes you would have to plug them in. They isolate external sounds well, but again depends on what external noises you're trying to isolate. If it's a herd of charging elephants, maybe they won't work, but normal street noises should be fine.
