Hi ​@Peter_254,

I had a look around and our internal information does say that this is a bug and the Play:1s aren’t supported as surrounds with the Arc Ultra. 

There is an official reply on the Sonos Reddit community from our team about this. What I have also supports that and says the “Play:1, Play:3, Play:5, Connect:Amp, or the first generation SYMFONISK Bookshelf or Table Lamp have insufficient computational power to support being used as rears with Arc Ultra due to the performance required for modern home theater experiences”.

I don’t see this being moved to a supported feature, and if you have issues later down the line then one of the first steps that’ll be suggested would be to un-bond the Play:1s from the Arc Ultra. I expect this to be fixed in a future update, so if you un-bond the Play:1s from the Arc Ultra then there’s no guarantee you’ll be able to in the future. 

It seems like the Play:1’s “computational power” is sufficient enough.

Seen 2 people before say that reset PLAY1s work as surrounds, and some that say they won’t

Maybe this “bug” is related to playbar being used before?

Looks like I might have to start following reddit to get Sonos official responses.

Bummer.

Any chance we could get anything "official" mirrored here.

Unless there’s another post, the official Sonos reply on Reddit stated:

For context: Play:1, Play:3, and Play:5s are missing the resources (CPU, RAM, etc.) to stream high-bandwidth Atmos audio. You can still group speakers with Arc Ultra if you want multi-room playback, but the early speakers didn't have Atmos in mind when they were made.

May have to unhide the reply to see it due to the downvotes.

 I keep reading that people are resetting speakers when they are removed as surrounds or sub.  Is a reset necessary?  Won’t they simple show as separate Sonos rooms until something else is done with them?

A reset is not necessary. If the device is already showing in the app, they are just increasing the process by resetting subs/surrounds to add back to the system again, so back to the same position they were at prior to the reset anyway.

In theory yes, but keep a factory reset of the surrounds in your pocket if you see odd things happening. 

The only time I could perceive a reset to be valuable is if you didn’t remove the surrounds from the first device they were bonded to. They’d be stuck in a state of waiting for that device to come back online, as they were bonded to it. 

This sounds like a BS justification, considering presumably all the Atmos processing happens on the Arc and all it's sending to the surrounds is a PCM audio stream for each channel that could be literally anything. Given that the Play1s can stream uncompressed PCM wav files (1400-odd kbps) from a local server, bandwidth also clearly can't be a constraint.

I was ready to pull the trigger on an Arc Ultra to replace my Playbar, dropping it into my Sub gen1 and 2x Play1s setup for now with the plan to replace everything else in future, basically committing to another decade of Sonos, but now I'm going to wait and see. If this is some artificial planned obsolescence nonsense then I think I'll sweat another couple of years out of my Playbar and then move to another brand.

This is beginning to sound like first evidence of forced obsolescence proved by users...oh dear.

i agree with you, alot of playbar owners might have bought ultra for straight swap, that won’t now, lost sales, guess sonos have crunched the numbers….tricky tech risk wise what will work in most homes...offer 100day returns again..

Without any knowledge about what this computational power would be used for in surrounds, we as users simply do not know if Sonos is honest about this. I tend to think they are…...