Hi N Oman, Dolby Digital Plus isn’t really supported via Optical connections, and your TV will even have the optical output disabled if audio format is set to Dolby Digital Plus. The Playbar can take a Dolby Digital 5.1 signal which sounds great and delivers full surround sound. From the  manual for the TV, it looks like if you go to Settings > All settings > Sound > Advanced > Digital out format and set it to Multichannel or Multichannel (bypass), you should get DD5.1 on your Playbar connected over the optical port, when that format is available.

You also may need to check on the settings for your various input devices that they’re set to send Dolby Digital sound too.

Sound is not only the format it’s being delivered in. Apart from the technical impossibilities set out above most TV’s do not sound better in DD+ compared to a Playbar in DD (non plus).

Thank you Ryan , excellent and complete answer. I see multi channel and multi channel bypass, I'll try when I get home. 

Cheers

Hi Ryan,

I have a similar problem to the OP. I am running a beam with two play ones as surrounds on my 2019 TCL ROKU 6 series. Using the built in streaming apps, I am only getting surround on the Dolby channel, Prime Video, and Disney+, as well as my local antenna (all of which call out 5.1 or Atmos in menu info). However, when streaming with Netflix, ESPN, YouTube, Hulu, Showtime, or HBO GO, I ONLY get sound from the beam. It seems to be stuck in Stereo for these programs. I’m plugged in thru the ARC and have tried audio settings on Dolby Digital, Dolby Digital, DTS, Auto passthrough, and Auto-detect all with the same results. Could you provide any insight on this and how I might be able to solve the problem or institute a potential workaround?

jj77 you do NOT have a similar problem. The OP is requiring DD+ support, which is not going to happen, you are after DD 5.1 support which should be available after some futzing with your hardware.