usually something like this (kind of standard Baxandall tone control) but there are some variations around.
Interesting. Always wondered how wide the adjustment was myself, only many manafacturers never show this. Although saying that, that graph looks like what used to be on really cheap plastic Hi-fi in the late 80's and early 90's, interesting to see that maybe their graphics on equaliser slider panel was actually roughly accurate and not just as most likely assumed just a way to make the front look a bit more busy or technical. Lol, God those things were horrendous though, I'm not an audio snob in a massive way, but those particular type things were really dire, was a strange time in Hi-fi, certainly the era where the industry really decided to divide between those with the cash and those that didn't.