Online Noise Gate: Learn How Threshold, Reduction, Attack, Hold and Release Actually Work

A noise gate is often explained in one line — "it cuts signal below a threshold" — but that line doesn't tell you how hold and release interact, or why a gate can chatter on real material. This interactive noise gate lets you load a sample track, move each control — threshold, reduction, attack, hold and release — and watch input, output and the gain reduction curve respond together, in real time.

A noise gate works the opposite way a compressor does: instead of taming signal that goes above a threshold, it attenuates signal that falls below it — useful for cutting hiss, bleed and background noise between notes or phrases. It's built to teach the process, not just illustrate it, part of AudioFxLab's free collection of interactive audio tools.

Parameter Guide: How Each Noise Gate Control Works

Threshold

On a noise gate, threshold works in the opposite direction from a compressor: it's the level below which the gate closes and attenuates the signal, not above. Everything louder than the threshold passes through untouched; everything quieter gets pulled down toward silence, or toward whatever floor the Reduction control sets.

Where to start: set it just above the level of the noise or bleed you want to remove, and just below the quietest part of the signal you want to keep — watch the purple zone on the input waveform to see exactly what the gate would classify as "below threshold" at the current setting.

Reduction

Reduction sets how much the gate attenuates the signal once it's closed, in decibels. It functions like a depth control rather than an on/off switch: a low value only trims the quiet parts down slightly, while a high value (60-80 dB) pushes them close to silence. This is different from an infinite-ratio hard gate — Reduction lets you dial in exactly how aggressively unwanted noise gets suppressed.

Where to start: moderate values (30-50 dB) are usually enough to make background noise or bleed inaudible without creating an unnaturally abrupt silence between notes; push toward 80 dB only when you need near-total silence in the gaps.

Attack

Attack is how quickly the gate opens once the signal crosses back above threshold. A fast attack (around 1 ms) opens almost instantly, which is important for percussive or transient-rich material where any delay would audibly clip the start of the sound. A slower attack softens the opening, which can sound more natural on sustained material but risks shaving off the very beginning of fast transients.

Where to start: keep attack fast (well under 5 ms) for drums or any material with sharp transients; only slow it down deliberately if you want to soften the gate's opening on smoother material.

Hold

Hold is a feature specific to gates — compressors don't have it: it's the minimum amount of time the gate stays fully open after the signal drops back below threshold, before it's allowed to start closing. Without hold, a signal that briefly dips below threshold, even for a few milliseconds, as often happens naturally, can cause the gate to flutter open and closed rapidly, an artifact usually called chattering.

Where to start: a short hold (20-50 ms) is often enough to prevent chattering on most material; increase it further, up to a few hundred milliseconds, if you notice the gate still closing and reopening rapidly during a single sustained sound.

Release

Once hold time has elapsed and the signal is still below threshold, release controls how long the gate takes to close, from fully open down to the attenuation set by Reduction. A fast release closes abruptly, which can sound choppy or unnatural on sustained sounds. A slower release fades the tail out more gradually, sounding closer to a natural decay.

Where to start: fast release (50-150 ms) works well on percussive material where a clean cutoff is expected; longer release (300-800 ms) suits sustained instruments or vocals, letting the natural decay of the sound finish before the gate fully closes.