No. If you go Sonos for HT your receiver and its speakers are redundant.

The Arc does not handle DTS formats, which can be an issue with some BluRay disks

I know the current speakers become redundant. That is kind of the point of going to Sonos. :-)

I only use streaming for movies, not Blu-Ray so I don’t see DTS as an issue.

But how do I get sound from the different sources like AppleTV and PS4 to the Sonos without the receiver as the connecting unit? There is only one hdmi in the Arc right?

The external sources connect to the TV HDMI inputs then the TV's HDMI-ARC port goes to the Arc.

But my TV is an older Panasonic TX-P50G10E, and as far as I know that has no HDMI-ARC, but the Yamaha receiver does as far as I have been able to find out. 

I would have thought it unusual for a receiver to have HDMI-ARC but I don't know that for sure.

Older Panasonic TVs are useless at passing through multichannel sound. Absolutely no chance of Dolby Atmos.  And there will probably be lip sync issues.

BUT this can be sorted out by buying an HDFury Arcana device (and possibly an HDMI switch). I have an Arcana and can thoroughly recommend it. It would make a big difference to your viewing experience with the Arc and an old Panasonic TV. 

Hi John

I think it does based on the section Video features on this page: https://dk.yamaha.com/da/products/audio_visual/av_receivers_amps/rx-a830/specs.html

Yes but that might be for taking the audio feed from the TV, not sending it to the Arc.

Hmm. Well a new TV is planned as well. But I had hoped to wait a while longer with that. 

But investigating this issue has caused me to stumble upon a lot of posts regarding Lip sync issues with the ARC, so maybe I need to reconsider this whole Sonos approach.

The Arcana sorts the lip sync issues but it's right to consider carefully if your current setup is working well.

We will be moving to a new house, and the new living room does not lend itself to front speakers, so a Soundbar would be better. And I would like to not have speakerwire crawling all over the place as well. But lips sync issues would be a total bummer, and honestly why is that even a problem in 2020 with a new product like the ARC?

It isn't the Arc. If you bypass the TV for audio there are no issues.  The Arc plays what it gets when it gets it.

How to bypass the TV?

Wasn’t using the TV and not a receiver the original recommendation?

I use the HDFury Arcana and an HDMI switch. Mainly to get Atmos over TrueHD with an older TV, but sorting lip sync is a bonus.

I have now spent as much time on this as I feel I can. I hope it has been of some use.