How To Use An Equalizer

Learning how to use an equalizer is a fundamental part of learning how to mix.

EQ (short for equalization) is one of the main tools you will use on a daily basis to craft sounds and fix sonic problems within the frequency spectrum in order to produce a mix that has a balanced frequency response and sounds like the records you hear on the radio or streaming platforms.

The good news is that despite all the geeky terminology around EQ, they are easy to use and to learn and in this blog post, I want to give you the very basics of an EQ plugin, describe the parameters that you’ll see on almost every EQ plugin and then the basic way to use EQ, so you can start using one and start crafting better mixes today.

Frequency Spectrum

Every sound sits within the frequency range of human hearing which is between 20Hz and 20kHz.

Every instrument has a fundamental frequency but also has higher overtones and harmonics that give its character or timbre.

Using EQ, we can change this character more to our liking should we so desire.

Knobs and Dials

So, what can you expect to see when you open up an equalizer plugin?

Some GUI’s are more complicated to look at than others but the EQ controls will always be the same:

• Frequency
• Q
• Gain

Frequency

This is the set point for certain filter applications or frequency that you want to change.

Q

This is the bandwidth

Gain

The loudness of the chosen frequency

Types

Bell curves look like this:

They allow the cutting or boosting of frequencies within a specific range

Shelf EQ looks like this:

A shelf EQ allows the boosting or cutting of all frequencies above or below a set point.

Filter EQ

There are two types of filter EQ’s:

• low pass filter (high cut)
• high pass filter (low cut)

The high pass filter (HPF) removes all the frequencies below its set point as seen here:

The low pass filter (LPF) removes all the frequencies above its set point.

This image shows all three in action:

How to Use an Equalizer

There are four main ways to use an equalizer:

1. Enhance nice-sounding frequencies
2. Remove bad sounding frequencies
3. Create space and separation
4. Change the sound to something completely different

Enhancing frequencies you like

This step isn’t always necessary because you might find that cutting the frequencies you don’t like first might be enough to clean up the sound.

The general rule of thumb is to use wide boosts and narrow cuts because this is what sounds most natural to the ear.

If a guitar isn’t cutting through the mix, you could boost it at around 2kHz to give it a bit more presence.

Removing frequencies you dislike

This is one of the main ways to use EQ and you might hear it referred to as subtractive EQ.

Unfortunately, there are going to be elements to a recording that you didn’t intend to record and that you just don’t like. A persistent ringing on a drum or harshness in a vocal or that annoying room resonance that plagues all your vocal recordings.

Using a narrow cut (high Q) we can remove these obvious problems in our audio. A surgical cut is a narrow cut and due to this narrow bandwidth, you can be a bit more drastic and go for a -6dB cut.

If you’re struggling to find the problematic frequencies that need cutting, try sweeping an extremely narrow boost up and down the frequency spectrum until you notice frequency ranges that sing out at you.

You can also use a subtle, wide-cut (low Q) to remove larger undesired elements of the sound, you don’t have to go narrow in every case.

If a vocal sounds muddy you could remove a lot of the bass with a -3dB low shelf at around 100Hz. If an electric guitar sounds harsh and ear-piercing you could add a wide cut between 4kHz and 6kHz.

Create space and separation

This is most desirable in a mix as it’s often one of the main ways to tell an amateur mix from a pro mix.

Whenever you boost a frequency range in an instrument or vocal, try cutting the same frequencies in the other tracks that have frequency content in the same range.

Boosting the vocals at 2kHz and 4kHz? Cut these frequencies in every other like-sounding instrument and vocal.

This is sometimes called frequency slotting and it’s one way to use EQ to create separation and creating mixes that sound full and clear and not muddy and cluttered.

Using high pass filters to remove the low, rumbly stuff in every track also helps with separation and clarity. Placing one on the main vocal at around 100Hz will not only help it to sit in the mix better but it will also help your vocal compressor to work more consistently.

Getting creative and changing the sound

A typical application to explain this use would be the ‘telephone’ vocal sound.

This is achieved by using a bandpass filter and centring it around the 1kHz region. Play with the slope settings of the filter to really get the tone you are looking for and fits the best in the mix.

Experiment with drastic filters and boosts, get creative!