Adjust low frequencies using the top row of Boost and Atten knobs and the CPS (cycles per second) switch. All low-frequency equalization is a gentle shelving type, 6 dB per octave.Boost mid and high frequencies using the KCS (kilocycles per second) and Boost knobs on the second row.Cut high frequencies using the 10k Atten knob located at the right side of the plug-in.