How to set up a noise gate

This guide uses the noise gate in patchd, a free effect on every channel, and its settings are organized exactly the way the guide is: the node panel groups its controls into beginner, intermediate, and advanced, so you can stop at any tier and have a working gate. If you want the concept first, start with what a noise gate is, then come back here to tune one.

The four settings that matter

A gate has one job: stay closed in silence, open for speech. Four controls decide how gracefully it does that, and they map to the four stages the gate moves through on every single word you say.

• Threshold (default -45 dB). The loudness line. Sit quietly, watch your level meter, and note where your room noise rests. Set the threshold a few dB above that and comfortably below your speaking level. Your voice crosses the line, the room never does.
• Attack (default 1 ms). How fast the gate opens once you cross the threshold. Keep it fast: a slow attack shaves the front off every word, and listeners notice missing consonants long before they notice noise.
• Hold (default 100 ms). How long the gate stays open after your level dips. This is what stops the gate from snapping shut in the tiny pauses inside a sentence.
• Release (default 150 ms). How gradually the gate closes once hold runs out. Too fast sounds choppy; too slow lets the room linger after every sentence.

Start with the defaults, speak normally, and move only the threshold until the gate opens on every word and stays shut when you stop. For most rooms that is the entire setup. Everything below this line is refinement.

Range, hysteresis, and the expander

The intermediate controls fix the two ways a basic gate gives itself away: sounding unnaturally dead when closed, and flickering when your voice hovers near the threshold.

• Range (default -90 dB). How far down the gate turns the background when closed. The default is effectively total silence, which is what most streams want. But total silence can read as "the mic just died" on a quiet podcast; raising the floor to something like -30 dB ducks the room instead of erasing it, which sounds more human.
• Hysteresis (default 0 dB). Chatter insurance. With a few dB of hysteresis, the gate opens at the threshold but does not close until you are that many dB quieter. Trailing off at the end of a sentence stops making the gate stutter open and shut.
• Downward expander (off by default, ratio 2:1). Turns the hard switch into a gentle slope: instead of slamming to the floor, quiet sounds get turned down by a ratio you control. At 2:1 it is barely noticeable and very forgiving for soft talkers; higher ratios approach the hard gate again.

The math, straight from the engine

Everything the gate decides, it decides in linear amplitude, so the first thing the engine does with your threshold is convert it out of decibels:

To know whether you are above or below that line, the gate tracks your level with an envelope follower: it grabs peaks instantly and lets go of them slowly, on a 10 ms time constant.

And the open and close moves themselves are straight lines: your attack and release times become per-sample steps.

The advanced controls are about what the gate listens to, not what it does. The sidechain high-pass (20 Hz to 2 kHz) and sidechain low-pass (1 kHz to 20 kHz)filter the gate's detection signal, never your audio. Raise the high-pass until keyboard thumps and desk bumps stop opening the gate; lower the low-pass if hiss or sibilance is triggering it. Between them the gate only reacts to energy inside a band you chose, which in practice means it only reacts to your voice. Your actual sound passes through full-range the whole time; the filter runs on a private copy the detector uses (a second-order Butterworth high-pass, for the curious, with Q of about 0.707, the flattest passband a biquad can give you).

Where the gate sits in the chain

Order matters, because every effect feeds the next. Run your cleanup first: a high-pass or EQ to remove rumble, noise suppression to strip the steady hiss, and the gate after them, so it sees a clean floor and the threshold can sit low. Put a compressor after the gate, never before it: a compressor raises quiet sounds toward your voice level, and that includes your noise floor, which turns a well-set threshold into a coin flip.

In patchd the gate is a free node in the effects rack on every channel. Drag it into position, set the threshold against the live meter, and the gated result is what every destination hears: your headphones, your stream bus, all of it. patchd is in development now. Join the waitlist and we will tell you the moment it is ready to install.