To be clear, i’d like to use my Play3s for my TV, with an Arc.

You have two options.  Connect the Arc to your display via eARC and then set the Play 3’s as the surround speakers. This is the recommended method.

Or

Setup the Arc to your display and then have the Play 3s  setup as a separate room in the Sonos App and then when TV audio is playing through the ARC then you would group in the Play 3s. Be aware that this method is designed for speakers that are physically located in different rooms, when you group them to play TV audio and they are actually in the same room you will hear a delay. 

hi vazandrew1,

 so i’ve purchased the Arc and I ‘ve got it setup with my tv. Through the app the Play3s are setup as a stereo pair. they are NOT playing with the ARC. How do i set them as surround speakers like you said. I don’t see any option like that in the app. Yes I’ve updated my app. Thx in advance.

update! Hi Vazanderew1,

 i’ve got all 3 speakers now working with the tv, but the Play3s are in as a stereo pair, not surrounds. Is there a big difference? Any idea how i would do that?

Question - I don’t have e-Arc on my TV so my Arc is connected via optical digital.

When I as it to add surrounds, it only shows my Amps from other rooms, not the Play3s that I want to use. How do I get the Play3s to show up?

First you must separate the PLAY:3 stereo pair.

I’d love to do that, but the Play3s don’t show up in order to separate them.

Turn off all your other Sonos devices and then restart your controller, it may then see the Play 3s.

If that works you may have set them up as a second Sonos System. Factory reset them and then ADD them to your Arc / Amp system.