What is Noise Gate?
A noise gate automatically mutes audio when the signal falls below a set threshold, eliminating background noise during pauses in speech. It "opens" when you speak and "closes" during silence—letting your voice through while blocking ambient sounds.
How Noise Gates Work
Input above threshold → Gate OPEN → Audio passes through
Input below threshold → Gate CLOSED → Audio muted
Noise Gate Parameters
| Parameter | What It Does | Typical Setting |
|---|---|---|
| Threshold | Level that opens the gate | -40 to -30 dB |
| Attack | How fast the gate opens | 0.5-5 ms |
| Hold | How long gate stays open after signal drops | 50-200 ms |
| Release | How fast the gate closes | 50-200 ms |
| Range | How much gain reduction when closed | -inf to -20 dB |
When to Use a Noise Gate
Good candidates for gating:
- Air conditioning hum between sentences
- Computer fan noise in pauses
- Room tone that disappears when you speak
- Consistent low-level background noise
Poor candidates for gating:
- Intermittent loud noises (use editing instead)
- Noise during speech (gate can't help)
- Very dynamic background (gate opens/closes erratically)
Gate vs. Expander
| Tool | Behavior | Sound |
|---|---|---|
| Gate | Completely mutes below threshold | On/off effect |
| Expander | Gradually reduces below threshold | Smoother, more natural |
For podcasts: Expanders often sound more natural than hard gates, avoiding the "pumping" effect of audio cutting in and out.
Common Gating Problems
| Problem | Cause | Solution |
|---|---|---|
| Words cut off | Threshold too high | Lower threshold |
| Chatter in pauses | Threshold too low | Raise threshold |
| Pumping/breathing | Attack/release too fast | Slow down timing |
| Unnatural silence | Range set to -∞ | Use -20 to -30 dB range |
Why It Matters
Noise gates solve a specific problem: consistent background noise that's noticeable during pauses but masked when you speak. While not always necessary, proper gating can significantly clean up recordings made in imperfect environments.
When gating improves quality:
-
Home recordings: Air conditioning, refrigerators, and computer fans create constant noise that gates eliminate in pauses.
-
Consistent room tone: If your recording space has a noticeable "sound" during silence, gating removes it.
-
Multi-track recordings: Gating unused microphones prevents bleed from adding up across tracks.
When gating causes problems:
| Scenario | Why Gating Hurts |
|---|---|
| Natural pauses | Clipped breaths sound unnatural |
| Varied background | Gate opens and closes erratically |
| Very quiet speech | Gate might not open consistently |
| Reverberant room | Gate cuts off natural decay |
The alternative approach: Modern noise reduction (spectral editing, AI-based tools) often works better than gates for podcast cleanup because it can remove noise during speech, not just in pauses.
Best practice: Reduce noise at the source first (quieter recording environment), then use gating as a polish tool—not a fix for fundamentally noisy recordings.