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What are the pros and cons of using EQ before compression?
How do compressors affect harmonics?
Learn how EQs and compressors interact and create excitement
Should You EQ Before Compression? Or Vice Versa?
There isn’t a right or wrong way to approach this and it’s really down to personal preference and your desired results. Both will achieve different results depending on where you place EQ and compression in your signal chain.
It is crucial that you are aware of these differences before you decide which one is right for you.
The Relationship Between EQ And Compression
To understand how the position of EQ in your signal chain alters the sound it’s important to understand the relationship between EQ and compression.
An EQ (or equalizer) exists to allow you to remove or accentuate frequencies of your choice. This can be done with a wide or narrow Q (the range of frequencies you are affecting). A higher Q value means a smaller range and vice versa.
EQ is one of the most important parts of audio production. Adding or removing frequencies can help glue your mix together and clear room for certain instruments. A common example of this involves removing low frequencies from instruments to make room for your main bass sound.
Compression, also a vital tool for mixing, affects the dynamic range of an audio signal. By reducing the volume of a signal, a compressor can even out a mix and be used creatively to add warmth, color and saturation.
Both are extremely important when it comes to mixing and so deciding whether to EQ before or after your compressor can make a huge difference.
The Relationship Between Compression And Frequency Content
While compressors are mainly gain reduction tools, they will also affect the overall tone of your sound too.
This is because compression will react to the most prominent frequency that is fed into it. For example, a kick drum will have a strong fundamental frequency around 50-75Hz and also include softer, higher frequencies in the transient and body of the sound. Here, the compressor only reacts to the low frequencies as they are the loudest.
To clarify, the whole sound still gets compressed (not just the low frequencies), but the compression will only activate when the low frequencies are present, which has a strong effect on the overall tone.
Consider a kick sound with a soft transient and loud boom. The boom gets ducked, but the transient stays the same. The result is a perceived loss of bass, which you can turn into a perceived increase in mids and highs with makeup gain.
EQ Before Compression
So we now know that compression has a relationship with frequency content. The compressor will be triggered by the loudest frequencies present but it will nonetheless affect the surrounding frequencies as well.
In this case, it can be really useful to insert an EQ before your compressor in order to remove unwanted frequencies before they are emphasized by the compressor. This can result in a smoother finished product as any unwanted frequencies have already been removed by the time the signal is compressed.
Once again, there is no right or wrong, however, it is good practice to use subtractive EQ before compression. Removing tight frequency ranges that you don’t want allows you to increase the perceived loudness of the frequencies that you do want.
Be careful though – you need to remember that whatever you do with your EQ will alter the compression. If you did decide to come back later and boost or remove anything, this will affect how your compressor works and you will need to recalibrate it.
EQ After Compression
Using EQ after compression has many benefits. For starters, your EQ settings will not affect the compression at all and you are free to make adjustments later without changing the compressor too.
The primary advantage of EQ after compression is you get much more precise control over the tone, as the compressor is not getting in the way of any boosts.
This can really help some elements stand out in the mix. If you boost a frequency before applying compression then it just gets squashed down again. But boosting after compression gives much more consistent results.
Whereas EQ before compression should be subtractive, EQ after compression tends to be additive.
Mix & Match
Of course, there is no correct way to set up your signal chain, as stated it’s really down to personal preference. Most often, people will opt for EQ before and after compression. There is no reason why you can’t EQ, compress, EQ some more and then compress again!
A common technique is to utilize a couple of compressors and EQs in your signal chain and make minor tweaks with each so you don’t end up working each plug in ‘too hard’. The bonus is any nuances or characteristics of each will be present in the mix which will ultimately add more depth.
There’s no reason why you can’t insert your DAW’s stock EQ, then compress, then EQ with a vintage channel strip emulator to add some nice coloring to the final sound.
As we always say, try experimenting with different signal paths, plug-ins and settings and listen to the results. Once you find something you like you’ll be on your way to creating your own signature sound!