Best answer by Ryan S
The PLAY:1 does not have a Line-In port, so it cannot be hooked directly up to an external audio source. Other Sonos components like the PLAY:5 and CONNECT have Line-In ports which you can use to play external audio to Sonos. For use with a TV you'd want to use the Optical input of the PLAYBAR for the best sound and experience. The PLAY:1 is a great surround speaker to use a pair with a PLAYBAR.
You can find some more information on how Line-In works with Sonos in this FAQ.