Sonos Arc & DTS via PCM on Panasonic UB9000....

Yes, this is correct. Try unplugging everything from power for a couple of minutes and test again.

Tried this but still nothing?

Disconnected the Arcana & plugged the Sky Q into the switch, then the out switch into the HDMI 1 ok the Sky TV & sound & picture came through fine.

So it seems the Roofull is working….🤷‍♂️

Having messed around with the switch, it seems as though the issue was the ‘auto switch’ function. 

I turned that off & I was able to get the switch to work, by using the supplied remote….👍

The only issue now, is there is a quite large sound drop while watching BBC 1.

I’ve checked all the cables & all seems well.

Is this normal when first setting it up, or is there a setting to be changed on the Arcana?

Are you getting the correct audio from the Sky Q? Does this only happen with BBC 1? It may just be the specific program you are watching. Night Sound mode on the Arc or a dynamic range setting on the Sky Q might fix the issue.

The correct audio is coming via Sky Q, I’ve checked Atmos films & it works, although the Sonos app just had a wobbly, so I have reset it.

The sound drop seems to happen when I enter the Sky menu (home button) & then exit it, almost as if it’s lost connection?

You are probably just experiencing what is described below which is completely normal with the Arcana:
 

From the Arcana manual FAQ:

I notice a short black screen / resync when starting a content that i didn't have or noticed when connected direct to TV?
All that is normal, you will have the same if you insert any device in between, like an AVR, splitter, matrix, switcher, video processor, and the more device you have in the same chain, the longer this will take, the only way to have that nearly not noticeable is SOURCE > DISPLAY direct since signal goes straight to panel driver. If menu is 60Hz and content 24Hz then there will be a resync like for any video format change, if you have SOURCE > TV, then sure you never noticed it but insert any device in between and you will have the exact same, just normal, HDMI resync.

Thanks for finding that out for me….

It does seem to ease off after watching the channel for a few minutes, but every time I switch to the Sky Q main menu & back again, there is a slight delay….

Is there an actual audio delay or does the sound just cut out for a few seconds while the Arcana is resyncing?

It’s an audio cut off, which would make sense with the info you sent me….

Another strange thing I noticed is the Sonos S2 app is no longer showing my Arc/Sub/One SL rears on the app?

Ive reset the app, but still nothing showing up on the app?

Unplug the Arc for about a minute and reboot your router and phone.