What is an Equalizer and which types of EQ exist?

Estimated reading time: 7 minutes

When we talk about the different types of EQ, we should first explain what an Equalizer is. In short, an Equalizer is a filter that affects only a certain range of frequencies, and works by amplifying and attenuating them. Sounds complicated?

To make it simple, an equalizer makes a part of your sound louder or quieter. Now it sounds simple, right?
However, the usable answer lies somewhere in between our two definitions…

Different kinds of EQ

We can split our Equalizers by many different aspects. For example, do they color the sound on their own or not? How many control points do you have? Do you have return information, e.g. an analyser? Let’s dive into EQs and take this apart!

EQs with analysers

First, we can „judge“ an equalizer by the return information it gives. This is in most cases an analyser. Logically, that part of the EQ analyses the signal and gives you visual feedback. You can see the signal before it hits the EQ, after it hits the EQ or in some cases – both! This is both very useful and slightly dangerous at the same time. Why is it useful? Of course, more information displayed is always good, and you can sometimes see something you cannot hear… your small speakers cannot push 40 Hz out but you can definitely see it on any analyser.

Examples of EQs with an analyser: FabFilter ProQ, most DAW EQs
Examples of EQs without an analyser: Waves API 500, most analog emulation EQs

An equalizer’s analyser is a very valuable tool, but it hides a pitfall! It is very easy to become dependent on it a bit too much, and start using it more than your own trusty ears!

Types of EQ plugins by control

To make a broad separation within EQs, we will begin from the ground up. The trusty filter, with only one band. The band can be a high pass (a.k.a. low cut) or a low pass (a.k.a. high cut) filter. For some of these you just control the frequency and that’s it (just enough for a lot of cases). If you want to get fancy, there are equalizer plugins that let you control the slope of the cut.

Examples of filter-style EQs: FabFilter One, Waves OneKnob FIlter, TAL-Filter-2

Moving up, some EQs will have a few bands with fixed frequencies. These frequencies will most likely be „tried and tested“ values. As a result, these EQs are called semi-parametric, since you can only control a few of the parameters. A lot of the vintage emulation plugins will be like this, or in general those characterful equalizers.

Examples of semi-parametric EQs: Waves API, Arturia Pre 1973

The next (and the most common) step is the parametric EQ. In short, you can add your own points, control the gain, Q, slopes and type of the point. In short, the most flexible and most powerful variation. These EQs are mostly clean, and in some cases „surgical“ (but there are exceptions). As a result, we will use these equalizers for most of our daily tasks since they are flexible, quick and easy to use.

Examples of parametric EQs: FabFilter ProQ, Waves SSL

Another group are the graphic equalizers. Remember your parents’ fancy Hi-Fi with a row of little sliders marked with numbers? That exists in plugin form, too! These EQs will have (a lot of) fixed frequencies for which you can change the gain. In a lot of cases, they will be of the characterful variety.

Examples of graphic EQs: Waves API 560, Voxengo Marvel GEQ

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Clean or characterful equalizers?

Next, we can split equalizers into clean and colorful ones. What does that mean? In short, some EQs will change the sound as soon as it is fed through them. On the other hand, others will keep it pristine and change only what you tell them to. Most modern EQs are clean and will impart no special character upon the sound by themselves. The vintage EQs, emulations and simulations will not be so transparent… that’s where the fun begins! Using a vintage EQ with character will both color your sound by default, and in most cases – change the way your equalizer bands act and interact! From cutting SSL and API modules, silky Neve and Summit units, to other tasty colorful EQs… half of your sound could be there just by loading the correct equalizer plugin!

Clean EQs give you complete, accurate and predictable control over sculpting your sound. Meaning you can modify almost every value and you will know exactly what will happen.

Examples of Clean EQs: FabFilter ProQ, most DAW EQs

Colorful EQs start by imparting their own sound, and that’s not all. The EQ bands themselves will often not be „flat“ – moving one will affect the others, changing the gain will affect the Q value, and so on. This heavily differs from equalizer to equalizer.

Again, there are two sides to this: do you want to sculpt your own sound completely on your own? Or will you use an EQ plugin’s character as a base to build upon? Or will you be somewhere in between? There is no correct answer here, as with most questions in music. More closer to reality – there is one correct answer per person.

Examples of Colorful EQs: Softube Summit Audio, Pultec emulations , most analog emulation plugins in general

Conclusion

Equalizers are definitely a very broad and complicated subject in general. Being one of the most used tools in music production, they are also extremely important! Today we might have only scratched the surface of EQs, but even this should point you in the right direction and improve your own knowledge!

Note that none of the divisions and classifications in this text are final and absolute – there is always a different view on the matter! In other words, use this knowledge as a foundation and try to learn as much as you can about equalizers and everything that follows!

Now that you know the different types of EQs, we would like to give you a list of best EQ plugins to make your choice easier.

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