I recently purchased the Sony Bravia OLED LCD TV Class A8H 65” along with the Sonos Arc. Upon connecting everything, lip sync problem was very noticeable. After reading numerous posts in Sonos Community, I started navigating the Sony TV configuration menus.
These are the settings on my Sony Bravia TV which solved lip sync problem for me:
Display & Sound
1. Sound - Sound Mode - Dolby Audio
2. Audio Output
Speakers - Audio System
Audio System Prioritization - On
Sound mode sync - On
A/V Sync - Auto
eARC mode - Auto
Digital audio out - Auto 1
Digital audio out volume - Max
Dolby Digital Plus Output - Dolby Digital Plus
Pass through mode - Auto
Give these settings a try if you have a Sony OLED LCD and are having lip sync problems with the Sonos Arc.
After entering above settings, I reverted Sonos Lip Sync to 0.
Cheers.