I'm really not trying to irritate you 😅 but all I can see on that graph it at 50% centre position, all frequencies are around 0db, with bass at 0% it cuts everything under 250hz by about 6db, treble at 0% as much as 13db. Highly asymmetrical, but it definitely doesn't seem flat at 0%, particularly in the highs, which I would have thought would be pretty noticeable on a Stingray pre?