Google: Watch YouTube on TV with 5.1 surround sound
You can watch YouTube videos on your TV with 5.1 surround sound. Enjoy YouTube’s library of shows and movies with support for other YouTube content coming soon on your supported surround sound system.
Turn 5.1 surround sound on:
Once you select a video to play, a player control bar will show. Go to 5.1 surround sound to turn it on or off.
Note: The setting will only appear for videos and devices that support 5.1 surround sound. 5.1 in YouTube is supported on all 2021 and later 4K TVs, Chromecast with Google TV, Playstation 5, and Apple TV. In addition, many 2020 and earlier TVs may also support surround sound. Check your device manufacturer to see if your device supports 5.1 for YouTube.
More motivation to upgrade. I could get a 5.1 USB hub adaptor for Chromecast with Google TV, or get a new TV. I have a feeling I'll be using the Chromecast with a new TV anyway..