Gain Control (or Boost/Attenuation) is the control on an equalizer that increases (boost) or decreases (cut) the volume of a given frequency range.

It is the main control of an equalizer, usually a knob or a fader.

• Center Position (0 dB): This is the neutral, or "flat," position. No effect is applied.

• Clockwise Rotation (+dB): You boost the selected frequencies, increasing their volume.

• Counterclockwise Rotation (-dB): You cut the selected frequencies, decreasing their volume.

This type of control is the basis for shelf), parametric and graphic equalizers. High-pass and low-pass filters do not have this control, as they only cut frequencies from a certain point, without the option of boosting them.