Maybe see if this video will assist you…
Thanks for the quick reply. I did watch that and follow the steps. My set up is slightly different - using coax be rca and I only want it in zone 2 of the Reciever so I have the output set to zone 2. With the volume when in pass through I can have it at 0 or max and it plays the same through the zone 2 speakers…
I would have expected the line-out level "pass-through" volume setting in the Sonos App ‘Connect’ settings to work - have you checked to see if there are any updates for your Onkyo Receiver?
If no updates, I would give the Onkyo support desk a call, or you could reproduce the issue and then immediately submit a Sonos system diagnostic report from within the Sonos App, note it’s reference and then contact/chat with Sonos Support Staff via this LINK and see what the Staff can perhaps suggest to resolve the matter.