Originally Posted by MrQuade
I am not 100% sure what the LG TVs do with an incoming audio signal that is already ARC compatible. Ideally, it would just pass the audio through without processing, and that would solve the delay issues since the TV would no longer be re-encoding the audio.
You could try making sure your XBox is always outputting Dolby bitstream audio rather than "Multichannel". The Multichannel mode refers to multichannel PCM, which exceeds the bandwidth capacity of ARC. If the XBox outputs a regular Dolby bitstream, which is ARC compatible, there is a chance that the TV will just let it on through.
You could also experiment with setting the XBox to output just stereo audio and see if that fixes the delay too. If so, then at least you know that the TV is able to pass stereo without any conversion.
Someone more knowledgeable on the LG's audio processing may be able to chime in and save you some experimenting though. It's one thing to know what a TV can do from a feature standpoint, but it is another thing to dig deep into the subtle ways in which it achieves those features that make the difference when you encounter problems like these.
Here is what my Xbox is set to:
Under Audio Output then under Speaker Audio I have "HDMI Audio" "Bitstream Out" the other options are "off", "5.1 uncompressed audio", "7.1 uncompressed audio" and "bitstream out". I tried 5.1 and this is the error I get: "There was a problem using this setting. Make sure your audio receiver supports it. Also, make sure to choose at least one audio setting. Both can't be turned off. (0x80bd0009).
So for whatever reason I can't use that, baffling. I seen this seems to be a common problem too, so I chose bitstream out. Then under Bitstream format I can choose "DTS Digital Surround" which when I select there is no sound at all, "Dolby Digital" which is what I have selected, or "Dolby Atmos for home theater (HDMI Only)".
I have tried several different combinations of things and it seems as if I am SOL unless I turn off the surround for PCM which fixes that audio lip sync delay but obviously not taking advantage of my surround sounds. Really sucking playing $2000 plus for a tv and then another large sum of money for Sonos speakers and beam sound bar.
I really appreciate your help so far MrQuade, not sure if I have many other options at this point.