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sevengroove
Contributor I
June 28, 2020
Answered

Audio delayed on Sonos ARC from native LG C9 TV apps

I’m experiencing an audio delay on my Sonos Arc whenever I use native apps like Youtube and Netflix through my LG C9 TV. All the settings I’ve found deal with delaying the audio further, but none let you do the reverse (i.e. delay the video signal or pull the audio signal forward). It’s a delay of somewhere between 100 - 200ms using this a/v sync test video, and it’s just about noticeable to be infuriating: https://www.youtube.com/watch?v=TjAa0wOe5k4

This delay seems much shorter when I watch the video through my Shield device, but I’d like to stick to the native LG apps because of better Atmos support. 

Any thoughts on why this might be happening and how to fix? I’ve looked at a couple of posts here and here but I don’t see a negative value for the audio delay on my TV sound settings. Here are my current settings:

C9 sound settings: Sound out set to HDMI ARC; Digital sound out set to Passthrough; e-ARC on; AV sync adjustment set to Off

Arc: TV dialog delay set to zero.

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Tylertron21Answer
July 2, 2020

I have the c9 and the arc.

What firmware is the c9?

Unplug the arc. Go into the sound settings when in a internal LG app playing audio. Turn ai audio off. Turn any sound adders off. Turn to passthrough and earc on. Turn off the LG using the power button (hold for ten seconds) unplug the tv, plug it back on and turn on.  Plug in the arc. Go back into the LG app and play audio. Go into audio settings again and make sure the sound is standard, make sure dolby is greyed out and on. Ai sound is greyed and off. Sound out to HDMI arc. Go into additional settings and set HDMI input audio to  bitstream.

I have no delay on my c9 with newest firmware 4.80.03 as long as all sources are bit stream and not Lpcm 

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17 replies

controlav
controlav
Lead Maestro
June 28, 2020

You need to switch to optical from HDMI. Many LG models add unnecessary delay in DD 5.1 pass through over HDMI, for reasons unknown.

Author of the leading independent Sonos apps for Android, MacOS, iOS, Windows and Xbox.
sevengrooveAuthor
Contributor I
June 28, 2020

That’s unfortunate - but if that’s true, how is there a difference between the delay on an internal app vs. an external HDMI source?

Switching to optical would beat the point of using a soundbar that I purchased specifically for its Atmos capabilities. 

controlav
controlav
Lead Maestro
June 29, 2020

That’s unfortunate - but if that’s true, how is there a difference between the delay on an internal app vs. an external HDMI source?

 

Because some at LG messed up, I would imagine. Different hardware and software paths for those signals.

Author of the leading independent Sonos apps for Android, MacOS, iOS, Windows and Xbox.
sevengrooveAuthor
Contributor I
June 29, 2020

Many LG models add unnecessary delay in DD 5.1 pass through 

Was thinking about this as well - Youtube doesn’t do DD 5.1, so how is there still a delay when I use this video to do an audio sync test?

sevengrooveAuthor
Contributor I
July 1, 2020

Bumping this up to see if there are other ideas.

controlav
controlav
Lead Maestro
July 1, 2020

Bumping this up to see if there are other ideas.


I already posted the workaround: switch to optical. Apart form LG fixing their firmware, I’m not sure what other idea you are looking for.

Author of the leading independent Sonos apps for Android, MacOS, iOS, Windows and Xbox.
sevengrooveAuthor
Contributor I
July 1, 2020

Many LG models add unnecessary delay in DD 5.1 pass through 

Was thinking about this as well - Youtube doesn’t do DD 5.1, so how is there still a delay when I use this video to do an audio sync test?

@controlav Do you know why this happens?

controlav
controlav
Lead Maestro
July 2, 2020

Many LG models add unnecessary delay in DD 5.1 pass through 

Was thinking about this as well - Youtube doesn’t do DD 5.1, so how is there still a delay when I use this video to do an audio sync test?

@controlav Do you know why this happens?


I’m a software guy, not a hardware guy, so I would imagine that someone messed up. Generally speaking audio/video stuff is complicated, but I fail to see why any device would have to do any processing on a pass-through audio signal via HDMI when it doesn’t have to do any with the same signal sent over optical.

Author of the leading independent Sonos apps for Android, MacOS, iOS, Windows and Xbox.
Tylertron21Answer
July 2, 2020

I have the c9 and the arc.

What firmware is the c9?

Unplug the arc. Go into the sound settings when in a internal LG app playing audio. Turn ai audio off. Turn any sound adders off. Turn to passthrough and earc on. Turn off the LG using the power button (hold for ten seconds) unplug the tv, plug it back on and turn on.  Plug in the arc. Go back into the LG app and play audio. Go into audio settings again and make sure the sound is standard, make sure dolby is greyed out and on. Ai sound is greyed and off. Sound out to HDMI arc. Go into additional settings and set HDMI input audio to  bitstream.

I have no delay on my c9 with newest firmware 4.80.03 as long as all sources are bit stream and not Lpcm 

    sevengrooveAuthor
    Contributor I
    July 2, 2020

    I have the c9 and the arc.

    What firmware is the c9?

    Unplug the arc. Go into the sound settings when in a internal LG app playing audio. Turn ai audio off. Turn any sound adders off. Turn to passthrough and earc on. Turn off the LG using the power button (hold for ten seconds) unplug the tv, plug it back on and turn on.  Plug in the arc. Go back into the LG app and play audio. Go into audio settings again and make sure the sound is standard, make sure dolby is greyed out and on. Ai sound is greyed and off. Sound out to HDMI arc. Go into additional settings and set HDMI input audio to  bitstream.

    I have no delay on my c9 with newest firmware 4.80.03 as long as all sources are bit stream and not Lpcm 

    I'm on 4.80.03 as well. I tried all the steps you outlined and did find a couple of things in my settings that needed cleaning up (my sound mode was set to “Clear Voice”, for example). Fixed all that but I’m still seeing and hearing the delay. All my HDMI sources are already set to bitstream as well, although I’m not sure why there isn’t a similar setting for internal apps. 

    Here’s a video I took on my phone of the delay happening on this audio sync test from YouTube: 

    You can see if you slow the video playback speed down that it hits after 200ms - maybe the phone capture added a few ms but it seems a tad longer than what I thought I saw on the TV, which seems to be closer to 100ms. Are you seeing better results on your setup?

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