Leonard King

Thanks for that info. I'm not really fussed about the sound bar powering down when inactive TBH. In fact it makes good sense. The power down during active use is a pain though, but as the Atmos signal can still be passed (via HDMI ARC ) even when not activated in the settings resolves it for me.

5 hours ago, td47 said:

@Leonard King It may well be the update, BUT have you ensured that you have the latest spec (2.0 or 2.1) HDMI cables in use that fully support all your required eARC or ARC functions? It might just be that the latest updates has made the TV follow eARC spec more stringently.

Yeah, cables OK: Belkin Ultra High Speed 2.1. I'm not too fussed to TBH as I can get everything via ARC as long as Dolby Digital Plus is engaged in TV's audio settings. I was more interested in whether this was a common issue or exclusive to my set and should LG be informed.

Having eARC engaged in the TV settings and sending Atmos etc to an eARC enabled Samsung sound bar causes the sound bar to power down after appx 18 minutes and diverts the audio to the TV's inbuilt sound system. Disengaging  eARC on the TV resolves the problem and still sends Atmos via ARC. This has only occurred since the most recent software upgrade. Anyone else experiencing this?

On 6/16/2020 at 1:43 PM, Nishanth Noble said:

I have connected by Apple TV on my LG C9 OLED TV. It is connected via HDMI. The TV is connected to Onkyo AV via ARC. While playing a Dolby Atmos enables movie, the AV receiver does not recongnize the output. But while connected the Apple TV directly to the AV, Dolby Atmos gets enabled. Though the HDMI Audio out is set to Bitstream why the AV unable to play Dolby Atmos. Please let me know if I need to make any adjustment in the settings.

Have you enabled Dolby Digital Plus in the TVs sound settings? It is essential to have this on to pass Atmos via ARC or eARC to a soundbar or processor.