If you’re using the Sonos optical adapter, there is no CEC involved, those type of signals are not carried across an optical cable. 

I’d be looking at a few things (and sorry, I haven’t looked for a manual, despite your kindness in providing the TV model). First, make sure the TV’s optical output is turned on. It may be always on, but some TV sets have an option to toggle that, worth checking. The other way to see this is to look at the end of the optical cable, before you insert it in to the Sonos adapter. If there’s a red ‘light’ shining through it, the output is working.

Next, check to ensure the TV’s audio settings are locked down to Dolby Digital, not Dolby Digital plus, or Atmos, those can’t make it through the restricted bandwidth provided with the optical. 

Since there’s no CEC connection, you’ll likely need to check that not only the TV is locked to Dolby Digital, but each device connected to the TV is as well. Things like your cable box, DVD/Bluray player, etc. Anything that’s sending a signal to the TV. 

While there’s a more significant expense, I’d start considering an upgrade to a TV that has either ARC or eARC. It would make life much simpler, and both those formats/connections have much greater bandwidth available (including Atmos, where it is used), and dumping the optical connection. 

Huh. Looking briefly for manuals suggests this is a 4K TV, which I suspect has an ARC port. Do you have a link to the appropriate user manual for your specific TV, rather than the generic ones I’m finding?

Page 30 of this manual:

https://downloadcenter.samsung.com/content/UM/201506/20150629123350828/ENG_HMUDVBADJ-1.309.pdf

Suggests there is an ARC port. If true, that is where your Sonos should be connected via HDMI, and not using the optical port, cable, and Sonos adapter. If you’re using that port as a ‘normal’ HDMI input, switch that device to another HDMI port, and connect your Sonos Arc there. 

Thanks Bruce,

I kept at it after posting this help post and when I ditched the optic adapter and switched the settings to the photo below it all started to work from Firestick apps! So happy as the sound is great! Just need to get a sub now and prey that is easier to connect to my antique Samsung 😁

Thanks again for the help

Charles

That setting will work when the Arc is connected to the ARC port. Yea, bad naming by Sonos, I agree. However, it shouldn’t make any difference when using an optical cable/adapter. Happy things are working for you now. 

The Firestick will probably send DD+ to the TV. DD+ cannot be sent via optical, and your TV can, again probably, not translate DD+ to DD.