First, it’s worth forcing a “check for updates” a couple of times, to be sure everything is up to date - for Sonos, the tv and if applicable the set top box. Then check that the program you’re watching is actually being broadcast in DD 5.1. In the uk, only certain channels, and even then not all programs, are DD 5.1 format. Then be sure the tv is sending out the right signal - in the Sonos app, the home page for the room should show you what format it’s receiving. 
 

Ensure you’ve got the Ones bonded to the Playbase, so they’re all configured as a single room. If you need to use the “group” feature to include the Ones, you’ve not got them set up correctly. 

Remember that the surround speakers are an effects channel - they won’t be sounding all the time like they do if you’re listening to, say, a Sonos Radio channel. If the app says the Playbase is receiving 5.1, listen out for those effects. 
 

Let us know how that goes, and if needed we can move on to try something else…

Thanks so much for the response. I appreciate that surround speakers do not always output sound and it also depends on the program/how it’s broadcast, etc. The One’s are also silent when playing music from the Sonos app, when using Alexa or Airplay from Music or Spotify, when they should be outputting equally to the Playbase (I do have them set to ‘full’, rather than ambient on the app) - they literally don’t output anything aside from the noises when setting them up, tuning them and Alexa’s voice (as I said - after Alexa stops speaking, the sound/music comes out of the Playbase, only). 

I have tested the system watching the same film I enjoyed in full glorious surround, when I first set up the speakers and they actually worked.

All products are showing as up to date as far as any updates are concerned. How do I go about ‘forcing’ a check for updates?

The one’s are grouped with the Playbase as part of a single room set up and worked fine to begin with for a few hours, it’s not like they’ve never worked, which is what makes it all the more frustrating to troubleshoot! When I manually alter the volume on the One’s, they increase the volume on the Playbase and so they are obviously still linked. 

Thanks again for responding!

For music playback (not TV input) go into the surround speakers ‘settings’ for the room that is the PLAYBASE, and set them to ‘Full’, not ‘Ambient’.

To check for updates, assuming you’re using the s2 app, go to Settings ( the gear icon, top right), then click on ‘Manage’, then scroll down and click on ‘System Updates’…

Thanks for the response - i did already state in my reply “I do have them set to ‘full’, rather than ambient on the app” 

I also checked for updates as you described and it says that it’s up to date, but was wondering if I was missing an inside trick to ‘force’ check for updates :-) 

Wondering if this is some kind of networking issue. trouble is - I’m clueless on those things!

By chance, is WiFi turned off on your Playbase?  This is an oft made mistake, because people think if the soundbar is wired you can turn off WiFi.  However, turning off WiFi turns off the WiFi radio. which is used for the 5 GHz direct connection between the soundbar and surrounds/subwoofer. 

Thanks for your response - my playbase is connected via optical to my T.V, but is not ‘wired’ to my router in any way. I’ve just checked the app and Wi-Fi is enabled (I guess it would have to be, to work!) 

The strange thing in your posts is that they are not playing anything, yet are connected (or they wouldn’t change the Playbase volume):

”The One’s are also silent when playing music from the Sonos app, when using Alexa or Airplay from Music or Spotify”. 

I think you may need to speak with Sonos support.  

Thanks so much for all input. After waiting nearly two hours for Sonos Support to answer - they were super helpful. Turned out to be a WiFi signal booster/range extender I had in the room that was playing havoc with the communication between devices. 

I’d forgotten we even had one! Still wouldn’t have ever thought that would be the problem. Literally, we unplugged it and all the diagnostic errors went away! 

All seems fine, just keeping fingers crossed it says that way and will have to have a re thing re the range extender issue. 

Thanks again and hopefully this thread might help someone else.