Fader dB scales are logarithmic: small physical moves at the bottom of the fader travel cause large level changes

A dB fader’s physical travel does not correspond linearly to level change. Looking at a fader strip, the dB markings cluster more and more closely near the bottom of the travel. A 1 dB change near the bottom of the fader may require moving it only a millimetre or two, making precise small adjustments difficult or impossible. Near unity (0 dB) the travel is more spread out, giving finer control per millimetre of physical movement. This is why the fader-at-unity method improves mix precision: keeping faders near 0 keeps them in the portion of the travel where physical movement maps reliably to musical changes in level.

Examples

Trying to reduce a channel by exactly 0.5 dB when its fader is at -20 dB: essentially impossible to do precisely. At unity gain, the same 0.5 dB move is a perceptible physical travel.

Assessment

Given the logarithmic nature of dB fader scales, explain why having faders sit near the bottom of their travel makes gain control harder and the fader-at-unity method easier.