Bax Level is a slang term used to refer to the volume of a person's voice, especially at the point their voice becomes annoying to listen to. While Bax level is often referred to in "stages", the interpretation of this is up to the individual, who may also refer to it typically on a scale of 1-100.
Braxton: Bruh shut the hell up man, I'm trying to focus. Bitch turn your bax level down.
Larry: What the fuck does that even mean?!