If you’ve got a 5.1 audio speaker system and YouTube it’s time to start enjoying enhanced surround with YouTube TV on Roku, Android TV, and Google TV. The audio format, long overdue for those devices, is now available with select programs to allow up to 5.1 channels of surround sound.
5.1 surround sound with YouTube TV was first available last year on Chromecast and smart TVs from Samsung, LG, and Vizio. Developers are still working on 5.1 audio for Apple TV, Fire TV, and game consoles.
Turn On/Off Surround Sound
You can turn surround sound on/off through the video player control bar (with select devices and TVs).
“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.”
Source: Google Support