Cleaning the optical cable ends and carefully vacuuming the optical ports on both devices, dust and dirt can play havoc.

Have you tried another optical cable? 

DD+ is not supported by the Ray. Use DD 5.1 instead.

https://support.sonos.com/en-gb/article/supported-home-theater-audio-formats

I tried both and I have the same issue.

Changing the cable did nothing

I tried Dolby Digital, PCM, same issues

Hi @Manu86 

@controlav is correct - please set your TV output to Dolby Digital.

Once done, please unplug your TV from power for at least 2 minutes and test afterwards.

I hope this helps.

I have the exact same problem, although my TV is a Philips. I tried restarting, removing power, cleaning the optical cable, and change all setting that has to do with sound (and i have no option explicitly saying Dolby Digital in its settings, so that advice cannot be followed). But to no avail.

The sound is fine except an annoying glitch every 5-15 seconds (i measured, and it is not consistent, but always within that range). It makes any kind of sound that is somewhat continuous (including all music, and most movies) unbearable to listen to.

I have not yet tried another optical cable, as that involves buying one. But eventually l will have to. Unfortunately i have had the Ray for months (i use it in one of two homes, so it took some time before noticing the issue, and then i tried to fix it, and even tried to live with it, which is now no longer possible), so a return on warranty is likely a long shot. But it is not usable for the TV as is. Music from/via the app is just fine, but i have other Sonos devices for that, so the Ray is/was intended for the TV.

Any hints on what i can try to fix this?

Hi @jedrake 

A regular but minimal glitch in TV audio generally means it’s time to reboot the TV. Please unplug the TV from power for at least a minute - unplugging will restart the TV’s software in a way that Standby will not achieve, and leaving it unplugged for a full minute will ensure that the capacitors in the power supply have fully discharged and thus power has left the TV’s circuits.

You mention music - if you hear the interruptions when playing a music source on your Ray (this does not include playing music on the TV itself) then I recommend you get in touch with our technical support team who have tools at their disposal that will allow them to give you advice specific to your Sonos system and what it reports.

I hope this helps.