LG B9 Optical Out Setup Issue with PS4 Pro

Doctor Hades

Well-known Member
Okay so the short of it is that I had DTS and DD5.1 working flawlessly with my PS4 Pro and my (ageing) Sony HT-SS1100 5.1 speaker setup for the past few years. I also use the amp with my Sony 4K UHD player via the co-axial output and my Xbox One X via the second optical out (VIDEO).

PS4 Pro connected to Sony amp via Optical Out (SAT).

Because the PS5 lacks an optical out port I have had to reconsider how the amp is setup for 5.1 surround sound. Luckily my LG B9 has an optical out port which I have never considered using until now (to be honest I forgot it was even there).

I have now connected the Sony amp to the TV via the optical cable (using SAT as by the PS4 Pro) and, obviously, my PS4 Pro is connected to the TV via HDMI.

In the PS4 Pro's Audio Settings I have set the sound output from Optical Out to HDMI since the optical cable is no longer connected to the console and instead the audio is being fed via the HDMI port. The Audio Type is set to DD5.1 (I also tried DTS but it is exactly the same).

On the TV, in the Sound settings, I have enabled the Internal Speaker + Optical audio output option (allowing the use of the TV sound and the amp for convenience) and set the Audio Type for HDMI 2 (which my PS4 Pro is connected to) to Bitstream.

However, when I watch a movie, say, Star Wars: Rise of Skywalker on Disney+ on my PS4 Pro the Sony amp shows the audio as PCM 48 MHz and only uses three channels. It is also really quiet.

Why am I not getting DD5.1 from my amp?

The PS4 Pro is outputting DD5.1 to the TV and the TV is set to Bitstream (not PCM) but I cannot get anything other than very quiet stereo sound.

What I am doing wrong?

Doctor Hades

Well-known Member
OK, so it seems it DOES work if I select a single audio source in the TV's Sound options, in this case Optical Out with Passthrough enabled and LG Sync set to Off. I then get DD5.1 or DTS (depending on what the PS4 Pro is set to) in the Disney+ app when watching Rise of the Skywalker.

It seems that it is not possible to have both the Internal TV Speaker + Optical Out for some reason. I suspect it might be because the Passthrough option is not available in this combination.
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Doctor Hades

Well-known Member
Not ideal but this TVs mic allows easy switching between the TV speaker and Optical via voice control so I guess this works fine.

Would have been nice to have had both Internal Speaker + Optical though so I could just use whichever I wanted without having to switch audio outputs.


Well-known Member
Thanks for updating...

So I'm kind of in a similar spot... I have plugged a ps5 into the hdmi 2.1 port on the LG and was hoping to have sound through the fibre optic also connected to the LG and feeding into a Yamaha receiver... ideally I would have a shiny new receiver that I could just plug the hdmi into for sound and vision... picture looks great but all quiet on the sound..

I'll have a play with what you have had a go with and see if I can get it to play... :)

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