There are a lot of tricks to get the sound of your podcast to have a professional polish, like using a noise gate. Find out how.
Here’s a common problem many new podcasters have. You’re recording yourself, or perhaps with a partner, and you think everything is going smoothly. Then you come back, listen to what you’ve done, and you hear a lot of noise. There’s a refrigerator humming, an echo from the other person, some birds chirping outside, and so on.
Suddenly you panic.
You just spent hundreds of dollars trying to soundproof this room. You put up acoustic panels and bass traps, you got heavy curtains and rugs. You did everything I advised in my segment on giving your room a budget sound treatment. Yet there’s still extra noise!
The noise is too distracting and you have to do it all over again!
And spend even more money on treatment!
Have no fear, there’s possibly a very easy way to help solve this. And for free.
A noise gate.
In this segment, I’ll talk about how to use a noise gate. And since Audacity is the recording solution for many new podcasters, then I’ll get specific about using it in Audacity.
What is a noise gate?
A noise gate cuts out anything under a certain noise threshold. Everything above the threshold will be heard clearly, everything below it will be cut. That means that if the noise in question is too loud, then it will still be audible, and raising the gate too high might threaten cutting your voice. It’s basically the opposite of a compressor: with a compressor, everything above a threshold is brought down, while with a noise gate, everything below a threshold is cut.
A noise gate can be both software and hardware. They come as guitar pedals, insert effects, and vst effects. For podcasting, I’d recommend applying it after you record, so that you can change the settings and see which one is best for that specific recording. If you use it as an insert, then you’ll be stuck with whatever you recorded, without the freedom of changing your options.
Finding the noise gate in Audacity
In Audacity – and all it’s forks – the noise gate can be found under the Effects tab. If you don’t see it there, don’t worry, it’s still free. Follow this link to download the noise gate. If you know where to install it, then drop the file there. If not, put it somewhere you can remember. Then follow the instructions on the Audacity Team page depending on what operating system you’re on.
About the noise gate in Audacity
The free noise gate that Audacity uses is pretty simple. And really, all noise gates pretty much work the same, so even if you’re not using the one on Audacity, this will still apply. Let’s take a look:
Nyquist’s noise gate, free for Audacity
We’ll walk through the options one by one.
Select Function
You have two options: to apply the noise gate or to analyze the noise level. When you run the analysis, make sure that you are playing back a “quiet” part of your recording, i.e. one without talking or music. The analysis needs to listen to how loud the background ambient noise is. It then gives you a good idea of where to set the gate threshold.
Stereo Linking
Essentially the selection for mono and stereo. When stereo tracks are “linked”, then they’ll be monitored and adjusted together. For podcasters, this is the way to go since your mic should have been recorded in mono.
Apply low-cut filter
This option allows the cutting of lower frequencies when the gate is active. Though it might be more useful to use a separate filter, this can act as a one-stop shop for those with deep voices.
Gate frequencies above
This is probably not useful for podcasters. When set to 0, the gate is applied to all frequencies (the setting you probably should have it on). When above 0, it applies to only frequencies above (essentially a low pass filter). If you have any shrill sounds, like a static hissing perhaps, then this might be useful.
Level reduction
This is how much the noise affected by the gate changes (also called “ratio” on other noise gates). If you have it to -100 dB, then the gate will cut off the noise completely. You might not want it at -100 dB. If you have it set to max, it could sound a bit choppy whenever you stop or start talking, so this is a good tool to adjust and see what sounds the most natural. Of course, get too close to 0 and you might not even hear it working.
Gate threshold
This is the level under which the gate will cut off the sound, or “close”. Any sounds that are below this, whether it’s the air conditioning or your breathing, won’t be heard. But sounds above this level, like your talking, will be let through.
Attack
Attack refers to how quickly the noise gate activates. The lower the attack time, the faster the noise gate works. The higher the attack time, the slower the noise gate works. When applied to an already recorded track, a software noise gate can usually “read ahead”, meaning that it will start the attack that amount of time before the noise threshold is reached. Some noise gates might have an extra “look ahead” or “read ahead” option, allowing you to set how far it looks ahead. You can’t set that with Audacity’s plugin though.
Hold
The one in the photo from my machine doesn’t have a “hold”, but it’s a common option. If the noise threshold drops, then hold says how long the noise gate holds before it begins to deactivate. This is important since in conversation, we have many natural pauses and stops. If you don’t want it to sound choppy, you might want a higher hold. But if you have too high of a hold, then the gate is almost pointless.
Decay
This is the opposite of attack. Where attack refers to the time it takes to open the gate and increase the level, decay refers to the amount of time it takes to close the gate and to reduce the level.
Preview
Notice the preview button. This will let you experiment with the different settings until you find one you like. As you’re testing it out, make sure you’re playing back an area with both your talking and silence, so you can see how the noise gate is affecting both.
How to use the noise gate
Whether you’re using Audacity’s noise gate or another one, you should first measure the volume of the ambient sound. This is the amount of sound that you don’t want playing while you’re talking. Note the ambient level. This ambient level is where to set your “gate threshold”. Now that you know where to begin, turn on the gate. Play the quiet part of your recording and adjust it until you hear nothing.
Next, you’ll want to to test it on your speaking. Find somewhere that includes silence at the beginning, then your speech, then silence again. It might be a good idea to run a test line before your podcast so that you can figure out the right noise gate setting. Do a tongue twister to warm up, for instance, and then start your podcast. You can use the noise around and the speech of the tongue twister to test the noise gate.
Now that you’re listening to the difference between the silence and the speech, you’ll want to adjust the attack and the decay, to make sure it doesn’t sound too choppy.
Noise gate tips
- If the decay doesn’t seem to be working, you might have your hold set too high.
- If things sound unnaturally quiet or too crisp, then experiment with your level reduction.
- If you’re applying other effects to your audio, I’d advise placing the noise gate first.
- Add some music from our service to make your show more complete
It’s a good idea for podcasters to learn their way around a noise gate. It’s one of the many important tools that you have at your fingertips that can turn your sound from amateur to professional. And you don’t need to hire anyone to do it.
