I am going to lose my mind trying to fix this... there is no fix. Only Samsung can fix this. I have swapped out all the HDMI 2.1 cables for new ones—no dice. Forget the audio delay settings... that just makes it worse, as the video is ahead of the the audio by milliseconds—not a big deal if this was a $300 TV and a $90 soundbar.
Support > Self Diagnosis > HDMI Delay > Slow 2
May help a little bit, and is the only setting to slow down video and not audio, which is the latency lip sync issue we are all having wiht the Q90R soundbar. I have it connected directly to the Q900R 8K TV via HDMI 2.1 and the lip sync issue is atrocious. Unacceptable and there is no fix; Samsung make this right or recall this soundbar!
What is the make and model of your TV, Brad?... and do you have the Q90R soundbar connectod to it?
Sorry it took so long. The TV is a UN55NU8000F. The Sound bar is a HW-K460/ZA. Connection between the two is optical. The Service provider is AT&T U-Verse. If I set the TV To Surround sound, the sound is wonderful with the tiniest bit of lag. THEN when the commercial comes on, the volume increases to the point that you have to yell to be heard over it. Without touching any controls. So you scramble to turn it down and then after the commercial, you can't hear anything until you crank it back up. I've given up and just use the Stereo setting and basically I've blown off Surround.
Stereo, no lag
Surround slight Lag, massive volume changes.
Have you tried using an HDMI cable as opposed to the optical cable, Brad? Also, have you installed the firmware update for your soundbar? Instructions are on page 30 of the user manual. If there is any 'auto level' settings for volme on the TV, itself, turn them on. The real reason is that ATT Uverse is considered 'streaming' so they can skirt the laws on on commercial volume control, and the new laws have not caught up yet. I used to have ATT... I cut all cords a few years ago and never looked back. I have Youtube TV with HBO and Showtime istalled on my 4K Amazon Fire Stick for half the price, no contracts, and no huge cable box! I've never had any volume issues and I fixed my own Samsung lip sync issues last night by installing and using YTTV on my Samsung Q900R TV instead of using the Fire Stick. Zero lip sync lag, which works for me until if and when Samsung fixes it... Have a pleasant day, CS
Switching to PCM will fix it, but is not a good solution since you will only get stereo sound. The 2020 TVs, which I think you have, have a setting for Pass Through under Digital Audio Output if eARC is enabled (Set to Auto). That is the solution. Surround sound will be in sync. If you don't have the pass though option, you are out of luck unless Samsung decides to add that to the 2019 TVs. Which they should, but you know....Samsung.
There is no such setting on my 2019 model and reverting to PCM (the difference is night and day between PCM and Dolby Digital +) is not an acceptable resolution for what I paid for this soundbar and what it is supposed to be and do... as of today, it is going back. I am over it. Samsung takes too long to make corrections and if they are not aware of this issue, then maybe its time that I stop buying their products all together. This is supposed to be their top tier soundbar coupled with their 8K TV, and they have a huge lip sync latency issue that makes watching it such a drag I just turn it off. Even in PCM, there is still a lag... just not as prominent, and again, that's not acceptable to me even if it did fix it. Dolby should work, period, the end... it's a soundbar! Thank you, nonetheless. I appreciate it!
Samsung refuses to release eARC for their 2019 models as they have moved onto their 2020 models. Sell your TV, buy LG and stop supporting this terribly customer unfriendly company. It's an expensive lesson learned for all of us.