fader
A fader, or zipper, is a rectilinear control knob that adjusts the level of an audio signal. It is mainly on the mixer slices. The low position corresponds to an attenuation at infinity, the high position usually corresponds to a unit gain. The indicated 0dB will then be -10dB relative to the unit level transmitted in the master bus. In low-end mixing consoles, the maximum gain of +10 dB may be the case. The curve of the faders is logarithmic.