A gate is like an automatic door. When your playing is loud enough, the door opens. When the signal drops below the threshold, the door closes.
The threshold must be set carefully. Too high and quiet notes disappear; too low and the noise remains. A noise gate lowers or mutes the signal when it falls below a chosen threshold. It is useful for pauses in high-gain rigs, but it cannot remove noise while the guitar note and noise are present together.
Threshold is the critical setting
Set too low, the gate barely closes. Set too high, it cuts off soft notes and the end of sustained chords. The correct point sits just above the unwanted idle noise and below the quietest intentional playing.
Attack
How quickly the gate opens after you play.
Release or decay
How naturally it closes after the note fades.
Placement
A gate before high gain controls guitar and cable noise. A gate after distortion controls noise created by the gain stage but may affect sustain more strongly.
Release controls how naturally notes end
A very fast release can make the signal close abruptly. A slower release allows the note to fade more naturally, although too slow a setting may leave noise audible between phrases.
Hear what the controls change
- Set the guitar and gain tone first.
- Listen to silence before adjusting the gate.
- Test quiet notes and long sustains.
- Use muting technique as well; a gate cannot replace clean playing.
- Stop playing and raise the threshold until the idle noise closes.
- Play the softest notes in the part and lower the threshold if any are lost.
When the effect does not sound right
Long notes die too early
Lower the threshold, lengthen release or reduce the amount of gain before the gate. A gate should follow the music rather than force every note to have the same length.
Noise is present while playing
That is normal for a gate. Reduce the actual noise source through gain staging, shielding, cables or power quality.