Friedman BE-OD Bass Control

[sonnyboy27]

I was wondering if anyone could explain the bass control from the Friedman BE-OD to me. From simulating it, it seems to be an active band-pass filter  where the pot shifts the center frequency. Anyone got any more info on it?

Build doc from the Thermionic Distortion for reference: http://www.pedalpcb.com/docs/ThermionicDistortion.pdf