Turn it Clockwise and a (Patent Applied For) circuit adds as much as 20db of active narrow band juicy MIDRANGE right where it does the most good, it?s like installing a wah-wah right where the distortion is being generated. But unlike turning on your wah-wah along with a distortion pedal, with the ?Freq. the bass and treble frequencies don’t disappear…Very unique, and not to be confused with a simple active or passive midrange control tacked on to the end of the circuit, as is the case with all other pedals you?ve tried with a ?Mid? control. Adding the ?Freq?s midrange imparts WAY more sustain and lets you easily place the guitar in the mix where you want it, irrespective of volume…..soundman’s not going to bury you anymore.