What is a fader?
A fader is the control used on a mixer or in a DAW to set a channel’s output level. On screen it usually appears as a slider you move up and down, and it plays the central role in balancing the levels of multiple instruments and vocals. Its position is generally shown in dB, where 0 dB is the reference position that neither boosts nor cuts the incoming signal.
What changes when you raise or lower it?
Lowering a fader sends less signal from that channel to the next destination. Raising it sends more, but pushing it too far can cause clipping later in the chain or at the stereo output. Adjust with your ears and with an eye on the level meter next to the fader.
How it differs from gain
Gain is generally used to set the input level near the start of the signal path, while the fader sets the channel output after processing such as effects. Lowering a fader does not necessarily fix a problem where too hot a signal is already hitting the plug-ins before it.
Moving it with automation
Fader movements over time, such as lifting the vocal slightly in one part of the song, can be recorded as automation. It is a musical way to compensate for performance variations that a single fixed position cannot handle.
Adjust in small moves
Because dB is a logarithmic scale, the same amount of travel changes the level differently depending on where the fader sits. Rather than making large moves in search of the right answer, decide which part is the lead and nudge the other parts up or down a little at a time, which makes changes in balance easier to judge.
Related reading
The setting that lets you undo fader moves in Logic Pro is covered in Things to Set Up First When You Buy Logic Pro (Japanese).
