Want to know how to remove those pesky resonant frequencies that are clouding up your beautiful mix?
In this article, we're going to cover everything you need to know to start removing resonant frequencies &, as a result, get cleaner sounding mixes.
How To Find & Remove Resonant Frequencies (Quick Step Guide)
- Turn the Q to the highest setting on your EQ plugin.
- Boost by 10db+ & solo the band for extra precision.
- Start sweeping the frequency spectrum & listen for tones that sound too harsh.
- Once found, reduce the db until it doesn't sound harsh or overbearing.
- Repeat for other pesky frequencies.
Don't know what you're doing? Let us explain it in a bit more detail…
Let's start with EQ sweeping:
What the hell's an EQ Sweep?
Listen, the days of sweeping chimneys are in the past, and all the cool kids are sweeping their EQ's now.
Wouldn't you like to be a cool kid too?
EQ sweeping, if you're not already familiar with it, is essentially using an EQ to pinpoint any resonant frequencies.
You can do this with a very small Q setting on your equalisation plugin, & by cranking the volume up.
With that EQ band solo'd & turned up, you'll sweep through the frequency spectrum & listen out for any frequencies that sound nasty or are overpowering.
But why would you want to find these resonances?
What do you do with them when you find them?
What Is A Resonant Frequency
So before we actually look into how to remove or fix anything, we should probably pinpoint what a resonant frequency is.
In short, resonance is something that occurs when 2 identical frequencies interact with each other, effectively doubling the amplitude or volume of the signal, causing a pretty horrible noise or tone that can affect mixes.
Why Would You Want To Remove Them?
Well, essentially its like having different frequency points in your signal be at different volumes.
The amplification that comes with resonance, can easily throw off the dynamics of your track.
Worse yet, when you go to the mastering stage, all of these resonant frequencies will become even louder, and start hogging a lot of space in the mix.
Sometimes you want your sound to be resonating all over the place (sound design usually), but it's not always what you want in a mix or master.
If you're dealing with resonance as a side-product, rather than as an effect, it can start to become a pain in the butt to deal with.
There are commonly 2 types of resonant frequencies in a signal.
Your low frequency (HUM)
Your high frequency (NOTCH)
Sometimes, when working in the lower end of the frequency spectrum, you can start noticing a horrible humming.
(btw please turn down your headphones)
This humming is caused due to the resonance at the lower range of the frequency spectrum.
This hum is a very common reason for a “lack of loudness” in your track.
Whenever you increase the gain, the hum will get worse, and take up a lot of space in your mix, essentially preventing you from achieving proper gain structure & a clean sounding result.
Cleaning out the humming resonances, can help you to solidify your low end and polish your track up nicely.
The second type of resonance, are notch frequencies.
You can find them at higher frequency range somewhere from 10kHz to 15kHz. Notch frequencies play above your tracks volume and can start feeling irritating when you listen to the track.
(btw please turn down your headphones)
There are some other frequency ranges at the middle of the spectrum but they are not as important as Hum and Notch.
Other than these two frequency bands, we should also be looking at another important category of resonance.
The Telephone Band
So I get what you're thinking…
We listed two categories, but this is a third.
What's up? Can't we count?
Well, this is a bit different from the other types we just ran through & we had to include it because it's an extremely sensitive range for human hearing.
You may not find overpowering resonances here, but more of an annoying scratch like sound.
What is the telephone band?
It's the frequency range, which is the most sensitive for human hearing, around 2.5-4.5 kHz.
It's the frequency band at which your phone calls are in, as well as the frequency at which a baby cries.
No wonder we're so sensitive to it.
Usually, if you're hearing some jarring, scratching sounds in your audio, it's a good idea to pop a bell curve filter in at around the 2.5-4.5 kHz spectrum.
Be careful though and use your ears, because removing too much might make your sound get lost in the mix.
How Do I Find A Resonant Frequency?
So we kind of answered this question already.
EQ sweeping. And it's pretty simple.
We'll be using the amazing FabFilter Pro-Q3 dynamic EQ plugin for demonstration purposes, but all of this can be achieved with any dynamic EQ.
If you'd like to find a good EQ plugin, check our best VST plugins article (it has an entire section dedicated to EQ plugins).
Let's say, you've got some sick vocal sounds, but they've been recorded in an untreated room with a lot of standing waves – the dynamics will sound like they're all over the place.
Before you try jumping to your compressor and squash the life out of your vocals, let's instead remove these resonances.
Drop a dynamic EQ on your channel.
Let's start with creating a simple bell curve filter.
Increase the Q all the way, so that your bell curve filter is only listening to a small band of the spectrum.
Also select the ‘solo' button so you can use it as somewhat of a band pass filter & listen closely to a small range of your spectrum. This will help you focus your hearing on the exact thing you're looking for.
Next, it's do what it says on the tin (or heading).
Sweep that point through your frequency spectrum, and listen for a tone that sounds like your resonance.
Trust your ears, and make sure to A/B between your dry and wet signal to locate the exact resonance that's messing your dynamics up.
How To Remove A Resonant Frequency, And Why You Should Do It!
Let's say you sweep through, and find that the frequency that's been bothering you is a D7 at a 2325 Hz
Now drop your gain and listen to your audio.
If you've located the correct frequency, most of the resonance should be gone.
Don't go overboard with your gain, remember, we want to tame the resonance, not delete the frequency from your signal.
Usually we would keep the gain between -3 to -7db depending on the source.
TIP: No amount of online tutorials will beat your ears. Proper ear training is key in dealing with resonance, but don't get discouraged, soloing your dynamic EQ band pass filter can help.
So you've found the frequency that's been messing with your signal amplitude.
Is this it?
Sorry to say, it rarely tends to be this simple.
The worse your recording environment is, the more resonance you'll have to fix.
It's not rare, to end up with an EQ curve that looks like a mountain range in Europe.
Having to tame up to 10 resonant frequencies in a single instruments channel is something everyone's had to deal with at some point.
Sadly it's one of those things, that you just have to do, if you want your recordings to sound professional.
Weird resonance is usually the first thing we notice in beginner mixes
Trust us, if you do the work, you'll be rewarded for it.
Secret Fabfilter Pro-Q3 Tip
Wow-zers, you've found the secret Pro-Q3 tip
Did you know, that when you hover your mouse over the spectral visualizer in the background of the plugin, it brings up in-depth resonance controls.
It highlights all the resonant frequencies in your spectrum, and makes it super easy to locate specific points and apply processing to them
In addition to that, it also points out where the exact frequencies of notes in your recording are.
This can be extremely useful if you're trying to accent some notes more than others in the mix.
But it has to be mentioned, that overdoing EQ is a sure-fire way to make your mix fall out of balance.
When mixing with EQ, to remove or boost resonant frequencies, you have to be careful not to overdo it to the point where it's affecting your audio quality.
How do you prevent making your audio horrible, I hear you say?
How To Remove Resonant Frequencies Without Affecting Audio Quality
As with many things in music, balance is key.
Don't remove enough resonance? You lose a lot of dynamics in your track, and your mix can feel “focused” on the resonant frequencies.
Remove more than needed, and you'll end up with a worse sounding recording, than you started with.
The amount of processing is very dependent on your source audio.
This is where no plugin or tutorial can help you, you just have to listen and try to trust your ears.
Overdoing corrective EQ is a quick and sure-fire way to remove all of the life from your recording.
Usually, it's best to think of it like this.
It's always better to have a little bit of resonance, than it is to have a dull sounding track.
Don't think of resonance as a bad thing, because it's not.
Resonance is an extremely useful tool for a lot of different applications, so before you commit to destroying all resonance from your music, you have to consider that you'll be losing a lot of melodic information.
In short, moderation is key here.
Don't overdo it.
Applying the appropriate amounts of processing, whether you're mixing instruments, vocals or bass, is essential to ending up with a professional sounding mix.
In short, tidying up the resonance of your audio channels and recordings is necessary, whether you're a pro in the industry, or just working from your bedroom studio.
Don't do it and your mixes will never feel as cohesive as if you had.
Overdo it however, and you'll start to lose dynamics from your audio.
There are some methods in music production, which require a good ear, and proper ear training.
Hopefully, after you've just read this entire article, and obviously not just skipped through while glancing at the bold words and pictures, you've now got a basic understanding of where to start with tidying up your frequency spectrum.
You know what else is an incredibly useful tool for music production?
Compression! That's right!
You might want to take a look at some recent posts of ours!
Here's a couple nifty articles on how to Nail your bass sound perfectly
Or if you just want to know what the hell a compressor is, check out this helpful guide on compression in music.