No 5.1 from LG OLED77C1PTB optical out?

Techno Freak

Standard Member
Hi All, just bought a new LG OLED77C1PTB.

I have an old Yamaha AV amp that does not have HDMI connections.

To date, everything routes through a Philips Hue Sync box, then to the TV via HDMI then optical out from the TV to the amp for surround sound.

No dice on the new TV though, the amp will only show pro-logic mode, no 5.1 from the optical.

I have re-tested the amp by running the Bluray player optical out direct to it and still get the 5.1, but via the TV I do not.

Same deal with the TV native apps, Prime, Netflix, Apple TV, Disney - none of them give me 5.1 on the amp via the optical out.

I spent hours going through the setting on the TV last night and no configuration of options gave me 5.1 though the optical. So frustrating.

Trawled the internet and it seems it should be giving me it, there were references to settings on the TV that I don't see to have on mine.

I did fine some posts about pass though not working with these sets, but that the native apps should be outputting 5.1.

I don't really want to buy a new amp, but even if I do, surely the native TV apps should be outputting 5.1 over optical? SO I would like to try and work out what's going on before I drop more ash on new equipment I don't really need/want.

I usually run everything via AppleTV 4k into Hue Sync then to TV then TV optical to amp. One possible workaround, which I'll try tonight, is the same set up but then set the AppleTV 4k to output it's audio to my old Apple TV 3rd gen and use that as the optical connection (no optical on the 4K Apple's), but like I say, I'd really like to know why the TV isn't natively outputting it's own content in 5.1 over optical.


EDIT to dd - updated to the latest available TV software last night too.


Distinguished Member
Just to be sure, you've set
HDMI input audio format = bitstream
digital sound output = auto
eARC = disabled

That is for regular ARC/optical usage.

There are cheap 4K 60hz HDR/DV audio extractors with optical, putting one of those on the output of Hue Sync box might be a way to bypass the TV.

Techno Freak

Standard Member
Thanks, but I couldn't find a setting for HDMI input audio format.

eARC settings are all greyed out (nothing connected to the eARC HDMI input).

digital sound output is set to Auto

I've had a look at those audio extractors as that could be the way to go, but it's bugging me that the TV itself isn't outputting it's own native content in 5.1. If I can figure that out then the pass though might "fix itself" if you now what I mean.

Techno Freak

Standard Member
Well, I gave up and ordered a new amp with HDMI connections. Shame as the old Yamaha has been a workhorse.

THEN had another go tonight and changed the “speakers” setting from “optical + TV” to “wired speakers” and blow me, the amp switched straight away from pro logic to Dolby Digital.

So, a new amp on its way for nothing.

EDITED to add, there’s no way for optical DD and TV speaker sound, if you want to watch just a regular show without running the amp you have to switch the “wired speaker” setting back to TV speakers.
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