Adding a stereo pair to an existing system.

If you added them to a new system and Paired them you need to reset them and open the controller to your old system and add them (individually) to it and then Pair them.

If you mean you added them to your existing system and now want to add them to the HT Room then you can't do that using the Sonos app. Third party apps can do that but the configuration is not supported by Sonos.

You might want to read the many topics here on adding unsupported speakers to a HT Room before you start.

Thanks very much for that Stanley,

Looks like I’ve got some research to do.

Thanks again,

Russ. 

I just bought two new 300's to use up front as a stereo pair in the hope of getting better separation.

Just to clarify… if you like to get best “separation”, adding a stereo pair in the front and grouping it with the home theater setup will do the opposite, because all channels are mixed up for the stereopair. 
So to achieve what you like, at the moment the unsupported way via 3rd party app would be the only solution. 

Hi Ralf,

Thanks for that. Can you tell I'm new at this? 😆 I can see exactly what your talking about now and I'm glad it didn't work for me because it would've sounded like rubbish.  

Would you happen to know the name of the 3rd party software?

Cheers Ralf and thanks again,

Russ.

Not sure of others, but Sonossequencr allows it. It’s been reported in another thread recently that it doesn’t help as much as was expected. While I have two PLAY:5 gen 2s flanking my Arc, I’ve never tried to set them up as Home Theater speakers, they’re for music only. 

Imagine a Sonos setup with a cut-down Beam or Arc, just keeping the center and height drivers, with that bonded to a pair of Era 100/300 right and left speakers. Sub and surrounds as options.

Think I'll make that an idea topic.

Edit did that.

https://en.community.sonos.com/ideas/discreet-tv-system-center-only-plus-right-and-left-sonos-speakers-6935231

That's a great idea. I love it.