Bitstream formats like Dolby Digital can add a fixed frame of buffering which is around 30 to 50 ms. The TV may also transcode from one format to another on the way to ARC which adds more time. Your bar then does decoding and its own enhancements which stack more delay. To reduce that stack feed the bar uncompressed PCM whenever possible. Set the TV to Passthrough and the console to PCM, disable surround virtualization and dynamic range compression on the bar, and run the TV in Game Mode with motion processing off. If you still hear late audio, use the TV lip sync or video delay control to hold the picture a hair longer.
