Demeter BEQ-PB Bass EQ Preamp Pedal is a pedal version of our famous on board Bass EQ. It has active equilization for treble, middle and bass. The treble and bass are both shelving controls with 14dB of boost and cut @ 6dB per octave. The middle control is a peak control with plus and minus 12dB of cut and boost @ 6dB per octave. A gentle slope of 6dB per octave was chosen because the amount of phase shift is greatly reduced and the resulting sound is both more cohesive and natural with very little of the comb filtering that would normally happen with a 12dB per octave approach. The unit also has a master volume control, internal gain trimmer (with up to 9dB of gain), a battery jack usable with any regulated supply (9 to 27 volts), a bypass footswitch, and an indicator LED. The unit was first designed in 1981 and was fine tuned with the help of Alfonso Johnson, Bob Glaub and Leland Skylar.