Ensure you have the physical surround setup, not using headphones or stereo speakers (whether laptop built-in or external, wired jack or wireless bluetooth) with virtualized surround effects.
Don't forget to change the configurations to 5.1 or 7.1 if your sound card supports surround sound but is previously set to stereo by default.
The Firefox app should also updated to the latest version and outputted to the surround sound card before using this extension.
