Beat Making
Noise Gates: The 8 Step Guide to a Cleaner Mix
Noise. It’s woven into the beautiful audio that we work so hard to record—often not by choice.
Your mix is where you translate your creativity into a polished finished product. The goal for all the individual tracks is to sit well in the mix and sound clear, concise and present…
But noise sabotages that effort. Unwanted noise in your audio signal is one of the most common—and annoying—issues in recording.
So how do you combat nasty noise and ensure that you’re getting a cleaner signal for better overall mixing?
The answer is Noise Gates. When used correctly, noise gates are a powerful tool that allow you to remove noise and other unwanted sounds from your signal.
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In this article I’ll show you all you need to know to get started using gates like a pro, including a handy step-by-step guide. Let’s get started!
What Is A Noise Gate?
Noise Gates, also known as gates or audio gates, are a type of dynamic processor that controls the volume of an audio signal. Noise gates lower the volume of a signal when that volume drops below a certain level, called a threshold.
Gates Explained
Noise Gates are part of the same dynamic processors category as your other common mixing tools like compressors, limiters, and de-essers.
Audio Gates come in many different forms: From free plugins to expensive hardware and everything in between.
Gates and compressors, like all dynamic processors, work specifically on the amplitude, or volume, of an audio signal—not the pitch.
Gates and compressors work on similar principles: they both affect volume in relation to a threshold (measured in dB).
Gates and compressors work on similar principles: they both affect volume in relation to a threshold (measured in dB).
However, where compressors attenuate, or lower, any volume that goes above the threshold, gates attenuate any volume that falls below the threshold.
So compressors make the loud parts of a signal quieter (more regular throughout) whereas gates make the quieter parts even more quiet (removing unwanted noise).
Gates work well on any sounds in a signal that may be quieter than the desired sound you are capturing (like a snare, or a tom).
Noise Gates will help remove:
- Ambient background noise
- Unwanted reverberation
- Crosstalk
- Static
- Small mistakes in performance
- Other instruments caught in the recording
Gates get rid of all that and let you shine! So now that you know what they are, and what they fix, here’s how to use them…
Gates work well on any sounds in a signal that may be quieter than the desired sound you are capturing (like a snare, or a tom).
How Noise Gates Work
Think of gates working like, well, real gates! Gates have two basic modes: Open and closed.
When the gate is open audio passes through freely. When the gate is closed, the audio is attenuated.
Whether the gate is open or closed to a specific volume is determined by the threshold. When the signal’s amplitude is less than the amplitude set by the threshold the gate stays closed and keeps that range of signal out. When the signal’s amplitude is greater than the amplitude set by the threshold the gate opens and lets that volume of signal pass freely through the gate.
Simply put, your threshold setting determines what sound gets in and what sound does not.
Open and Closed are the basic modes of operation, but the signal can be further shaped and structured by the different controls of a gate. The basic controls of a gate are:
- Threshold (measured in dB): Specifies the point at which the gate opens
- Attack (measured in mS): Time that it takes for the gate to open fully once the threshold is exceeded
- Hold (measured in mS or S): A minimum amount of time that the gate must stay open after the threshold is exceeded
- Release (measured in mS): Time that it takes for the gate to fully close after the signal falls below the threshold. Sometimes also called Decay.
- Range (measured in dB): The amount (dB) of signal the gate allows to pass even when it is closed. Rather than eliminating the noise entirely, it can be controlled and limited. It’s also sometimes called the Floor depending on your plugin or gear. Note: Not all gates have this.
Here is what a standard gate looks like in Ableton Live:
Seeing (and Hearing) Noise Gates In Action
A classic use of gating is cleaning up a snare recording. When you’re recording live drums, you’ll likely have the whole kit playing/recording simultaneously in a single room. Even with directional mics, you’ll still pick up some of the other drums (plus any room noise) in your recording.
So why is this bad? Well, if you want to make edits or add FX to just your snare, you need to isolate that snare in the recording without any of the other drums’ transients. This is where gating comes in!
Once your gate is correctly applied, your snare sound should be isolated from other sounds in the recording and thus more easily manipulated in the mix. This use of gating can be applied to any recording or sample you’re working with.
Here’s and example of a rough snare recording with no gating:
There’s a lot of unwanted signal in that recording, so it’s less than ideal for applying effects and other processing. Gating will fix all of that…
Here’s the snare after applying a noise gate:
The snare is more isolated and the bleed of the other drums is gone. This will make the snare a lot easier to work with in the mix, and will respond better to effects and processing later on.
Here’s a handy step-by-step guide to show you how I cleaned my recording up.
For this example, I’ll show you how I gated the snare from the example above, but the same concepts can be applied to any recording or instrument.
How-to Use a Noise Gate in 8 Steps
Step 1: Patch your gate inline
Patch inline. You always patch gates inline, assuming you are using it normally.
That means applying the gate directly to the track you want to affect, rather than creating a separate return track. If you’re using a DAW, it’s probably a simple drag and drop!
Step 2: Set Everything at Minimum and Threshold at Maximum
Set all controls to minimum, except the threshold. Leave the threshold at maximum. With these settings all sound will be gated, so you should hear nothing during playback of your recording.
Step 3: Slowly Lower the Threshold
Slowly lower the threshold until signal is passing through the gate. You’ll begin to hear the transient of your snare (or any instrument).
Step 4: Find your Sound
Continue to slowly lower and raise the threshold until you are receiving only the direct sound of the snare, with no other unwanted instruments or noise.
It might sound weird, clicky, and choppy at first — like you’re missing the tails or even body of your sound and maybe hearing mostly only attack. Don’t worry, it’s normal!
Keep shaping and everything will be okay! Step 5-8 is where you’ll bring back the bulk of your signal (and make it sound better) while still keeping it isolated from those unwanted sounds.
Step 5: Set the Attack
The Attack controls the time it takes for the gate to initially move from closed to open.
Raise your Attack until the gate is opening smoothly and the attack of your signal sounds normal and clean.
Listen just for the initial onset of the sound, and find the sweet spot where it sounds good.
Listen just for the initial onset of the sound, and find the sweet spot where it sounds good. Don’t worry about the body or tail of the sound just yet.
Step 6: Set the Hold
Hold is the amount of time the gate remains open before closing again.
Raise the hold until the gate is opening for a sufficient amount of time to capture the entire duration of the signal, as well as any other associated sounds that occur nearby if they are important to the signal’s character and quality.
It takes some practice, but is all about listening.
At this point you should have a clean, isolated (if not slightly unnatural-sounding) signal. It takes some practice, but is all about listening.
Step 7: Set the Release
The Release allows you to control how gently your gate closes. Use your release setting to avoid any abrupt cuts at the end of your audio when the gate closes.
Raise your release until the gate is closing at a rate that allows for your signal to fade to silence with a smooth conclusion, but before the next attack of the instrument occurs.
At this point your signal should sound more natural.
Step 8: Adjust the Floor
The Floor (or Range) function controls how much signal passes through the gate even when it’s closed. This allows you add back in a little (or however much you want) of the noise / background sounds in the original audio, which can help your recording sound a bit more natural.
Raise the Range (on this gate it’s called the Floor) until you feel that the signal is sufficiently isolated, the noise is reduced, and the signal still sounds clear and complete.
Hot Tip: you don’t have to add any back – the Range could be very low, or very high, it all depends on your needs.
So listen close, trust your ears, and noise gate accordingly!
Sounding Great With Gates
If you followed all these steps correctly, you should have a clean, isolated signal that’s free of unwanted noise.
Working with cleaner signals allows you to edit and add FX without affecting other instruments or unwanted noise.
Gates are all about listening to what sounds best to you. Always listen to your tracks in the mix. How a track sits in the mix ultimately determines how any signal needs to be gated.
So listen close, trust your ears, and noise gate accordingly!
Practice, practice, practice on many different types of recordings. Learning how to gate properly will give you cleaner signals. Which means a better mix AND a better master.
J'vlyn is a DJ, audio engineer, and A/V artist, with a passion for empowering queer and feminist narratives through audio/visual experiences.
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