Hi @Ian Sim 

Welcome to the Sonos Community!

I have an Amp connected to my TV and see this volume change when turning on my TV too. I don’t have a Sub, however, so I can’t compare.

What I can do, however, is look at what your Arc says about the process, - please recreate the issue, then submit a support diagnostic soon afterwards. Report the number given here and I’ll take a look. If you have more than one Arc, please let me know which one to look at. Thanks.

In the meantime, please try disabling and re-enabling the Sub instead of removing/adding it. Settings » System » Âroom with Arc] » Sub Audio » Sub. It may have the same result, and will be easier.

Hi Corey, I tried your suggestion, but the sub still doesn't unmute. Still need to go through the hassle of removing and then adding it back. Anyway, here's my diagnostic number 572479474

 

Thank you! 

Hi @Ian Sim 

Thanks for sending that - I was immediately able to see what I think is most likely to be the issue.

Please permanently disconnect the ethernet cable going to the Sub - the Arc expects the Sub to connect via a dedicated 5GHz link, and Home Theatre satellites (surrounds and subs) just don’t like being ethernet-connected.

In addition, I noticed the only other ethernet-wired device (the Bookshelf in K’s room) has it’s wireless interface disabled - as you’re using a mesh WiFi system, I recommend you re-enable this so that all your non-portable speakers can connect via SonosNet - only if you can connect this speaker to the main mesh node, however. If that room is distant from the rest it would be better to connect the Arc to ethernet instead, if that’s an option. If you don’t experience any issues (like missing rooms or interrupted music) other than the one you described, I think you can safely ignore this paragraph.

I hope this helps.

Hi Corry, thanks for your suggestion but I can't remove the ethernet cable. I've disabled the WiFi for the Sub but the issue still persists.

 

As for the ethernet cable, I leave it on as my sub has had connection issues with my WiFi and its  has so far been the only way for me to keep it connected to my system. 

Hi @Ian Sim 

The Sub doesn’t connect to your WiFi - it connects to your Arc. I do see a high count of transmission errors at the Arc, as well as some high peaks of interference. These could easily get in the way of the Arc and Sub negotiating a connection. Please remove any WiFi devices from within 1m of the Arc (except those that can’t be moved, like the TV).

Please re-enable the WiFi interface on your Sub and disconnect the ethernet cable.

If the Sub doesn’t connect after that, please connect the Arc to ethernet instead, if possible, and try again.

If the Sub simply will not connect to your system without an ethernet cable being attached, please submit a support diagnostic with the Sub’s WiFi interface re-enabled and ethernet connected. Thanks.

 

Hi Corry, I've tried but I am unable to connect my sub to the network without the ethernet cable. Here's my diagnostic number 1709435030. Thank you! 

Hi @Ian Sim 

Apologies for the delay - I’m not sure why I wasn’t notified by the system of your reply.

I was hoping to see something obvious in the diagnostics, but it’s not clear to me why the Sub will not connect via wireless. I highly recommend you get in touch with our technical support team for some real-time, step-by-step troubleshooting.

Thanks Corry, will do! Thanks for all the input