Added speakers? Do you mean surrounds bonded to your Arc?

Either way, a home theatre system generally has the dialogue channel directed through the front centre channel. The rears are intended for directionally placed audio effects. 

Oh that’s a shame, I would’ve liked to have had the option to have the dialogue through my One SL speakers. 
Anyway thanks a lot for your reply on this matter nik9669a

Another question, why doesn’t my sound system connect when I turn my tv on right away?  It comes on eventually but I have to wait. There’s other times I have to move to another channel for the sound to connect. 

In settings go to the room with your Home Theater > scroll down > Turn on TV Auto Play.  Let us know if that resolves your issue. Sometimes it has to do with the cable box making the “hand shake” to understand that it’s being requested to send picture and audio. I think your changing the channel to get audio was more of a coincidence with the handshake being completed. Also if your smart TV likes to display a banner of sorts try disabling it if possible.

It’s already set to TV auto play AjTrek1

In that case it’s probably what I suggested being the “handshake” process. I have the delay as well for audio but it’s not more than 10 seconds. To put it in perspective I didn’t have the delay until I was forced to change cable  providers. Their equipment can operate differently from one provider to another.

As a proof if you are able to do so…temporarily disconnect your cable and plug in an Over The Air (OTA) antenna. I had to do so recently when a snow storm knocked out my cable. Using the OTA antenna (I keep for backup) the video and audio were both instantaneous with no delay.

A final note..,I’ve made the assumption that a cable provider’s equipment is involved. If so and the delay is too long I suggest contacting them regarding the issue. You can also run a diagnostics within 10 minutes of the next occurrence and post the reference ID in your next post. After doing so call Sonos tech support to discuss the diagnostic.

This didn’t happen before so why all of a sudden it’s doing it now. I shouldn’t have to make any changes as I haven’t. 

Didn’t suggest you NEED to make any changes. I do suggest you follow my last two suggestions to contact your cable provider (if one is involved) and/or run the diagnostic as suggested and contact Sonos tech support. People in this community don’t have the ability to delve deeper into issues that can’t be resolved by trial and error or are hidden. Therefore the suggestion to use the diagnostic tool or contact a 3rd party when their equipment is involved.

Thanks AjTrek1, I appreciate the time you’ve put into this for me. I’ll have to give Sonos a call and see what they think.

Sometimes manufacturers will push updates to you. That might be tv, setup box, router… (Sonos gives you the option to turn Autoupdate on or off.) Any of these can affect in unpredictable ways a system that was previously working. I’m not saying this is what’s happened here, but it’s not impossible. 

Thanks nik9669a

Sometimes manufacturers will push updates to you. That might be tv, setup box, router… (Sonos gives you the option to turn Autoupdate on or off.) Any of these can affect in unpredictable ways a system that was previously working. I’m not saying this is what’s happened here, but it’s not impossible.

I’ll try disconnecting it and see what happens. 
thanks farhan123