The Ultra and Era 100s are NOT compatible with the S1 app:

https://support.sonos.com/en-us/article/sonos-app-version-compatibility

When was the last time you restarted your phone and your router? Try that first.

If you did Advanced Trueplay with the Ultra, retune with Trueplay again, but DO NOT use the advanced function.

Also try resetting the app on your phone and reconnecting to your system.

Thanks for your reply. I have read the link and now realised that the Sonos app I was using with the Beam and Eras was possibly an earlier version of the current Sonos app.

I have now restarted my Android phone and the router and retuned the Ultra and the Eras.

Still the surround sound was not loud enough and there doesn’t appear to be a way of adjusting the volume on the app, except for selecting the distance of the speakers from the user’s seat. 

I then thought that I could try to adjust the loudness using the volume slider on each of the Eras and that has done the trick. 

Is there not a “bias” volume adjuster for the surrounds any more in the Ultra’s settings? You may need to scroll down the room Settings page to find Surrounds Volume. 

If you have individual volume sliders for the Eras, are you sure you’ve set them up as surrounds? 

nik9669a wrote

Is there not a “bias” volume adjuster for the surrounds any more in the Ultra’s settings? You may need to scroll down the room Settings page to find Surrounds Volume. 

I can’t find a ‘bias’ volume.

When I select system settings I can select the Arc Ultra from the ‘Your system’ section, from the ‘Products’ section I can select Arc Ultra which then displays a ‘Status’ section (showing Microphone, Voice assistant, Network, Bluetooth), a ‘Connection’ section which is greyed out , enabled WiFi. The same ‘Status’ section is displayed when I select either Era 100.

The control that adjusts the volume between front and rear speakers for TV audio is shown in the App as ‘TV Level’ - slide it right to shift volume to the rear speakers, particularly when playing surround sound audio. See highlighted screenshot from the Sonos App.

For music audio, simply swap the ‘Ambient’ option to ‘Full’ for music playback - that’s also highlighted in the attached screenshot. Both feature settings are located in the HT room ‘Surround Audio’ section.

nik9669a wrote

If you have individual volume sliders for the Eras, are you sure you’ve set them up as surrounds? 

The volume sliders I adjusted are the ones on top of the speakers.

I believe I did set them up as surround speakers when I selected system settings a text box message appeared which said something like ‘Add surround sound’ and I remember seeing a diagram of a TV and two speakers and having to select the speaker which was making a sound.

When I select the Arc Ultra from the ‘Your system’ section on the system settings screen, there are several sections displayed; Name, Products, Sound, Home Theater, Voice etc. In the ‘Sound’ section I selected ‘Surround Audio’ where there are two level sliders for TV and Music. These are both set to the midpoint on the sliders. I didn’t adjust these. Below the ‘Surround Audio’ section is the ‘Surround Distance’ section which offers three measures of distance from the seating position.

I have now found the solution by using a mix of adjusting the sliders on the speakers, the sliders in the surround sound section of the app and the surround distance setting.

All is well, thanks for your suggestions.  

Thanks Ken, that’s really useful to know. May I suggest that a couple of words could be added to the TV and Music sliders to indicate that the slider controls the front and rear bias.