fader

Imagine a sound engineer at a mixing desk, gently pushing a slider up as a singer begins and pulling it down as the music softens. That sliding control is called a fader. It is mainly used in audio equipment to raise or lower the level of sound in a smooth, exact way.

The word is most common in music production, radio, live sound, and DJ equipment, but it can also be used for similar sliding controls in lighting or video systems. In simple terms, it is the part you move when you want a sound, light, or signal to come in, go out, or sit at just the right level.

A fader is usually a sliding control that changes the level of an audio signal. You see it on mixing consoles, studio gear, DJ mixers, and other equipment where sound needs to be adjusted smoothly. Instead of turning a round knob, the user moves the control up or down, or side to side, to make a voice, instrument, or full track louder or quieter. Because the position is easy to see, it helps engineers make careful changes during recording, broadcasting, and live performance.

The word can also be used for similar controls outside pure audio. In lighting, video, and some electronic systems, a fader may control brightness, intensity, or another signal level in the same smooth way. This broader use still keeps the same basic idea: a physical control that lets someone bring something in, lower it, or balance it with something else.

Less often, the word may be used loosely for something that makes another thing fade, but that is not the main everyday meaning. In normal use, people usually mean the slider on professional or consumer equipment that controls sound or another signal level.