Analogman took the great distortion pedal of Maxon and twicked, added a Mid range knob, to add some mids, since they seems to disappear in the extreme settings of the knob tone. From analogman: "The SD9 sounds pretty good stock with the tone knob rolled all the way down, but very little high end. When you turn up the tone knob, the low end is decreased and you get a scooped mids sound, which I dont like. At high tone settings, low end is VERY weak... After our mods, the low end stays strong and there are no scooped mids. The high end is also softened a bit for a nicer tone"