A Simple Guide To EQ
In music production, EQ (equalisation) is one of the most important tools for mixing a track. It can be used to boost certain frequencies (pitches) and to remove unwanted frequencies as well.
This addition and subtraction of frequencies helps the individual sounds in a track fit together so that they're not clashing and causing 'muddiness' (lack of clarity).
One of my music production mentors once used the analogy of EQ being like a frequency 'jigsaw puzzle' where adding and taking away frequencies of the sounds in a track makes it fit together sonically. The trick is not to overdo it though, as the sounds might sound to separate from each other. It's all about finding that balance.
In this blog we're going to go through a simple guide to EQ, where I will break it down into separate sections and run through the different aspects of equalisation in a digestible way.
The sections we're going to talk about are: Overview of Frequencies, EQ Components and Terminology, Corrective EQ and Creative EQ.
Overview of Frequencies:
As this blog is a simple guide to EQ, I'm not going to get into the physics of what exactly frequencies are scientifically, but instead going to talk about frequencies as pitches.
Basically, the higher the frequency, the higher the pitch. Frequency or pitch is measured in Hertz (Hz), much like length is measured in centimetres or inches.
The human ear can hear from 20Hz to 20,000Hz or 20KHz but we lose the ability to hear higher frequencies as we get older. 20Hz is extremely low pitch and 20KHz is very high pitched
EQ Components and Terminology:
Now, to use EQ properly you'll need to understand the different components of EQ plugins/hardware units. I'm going to use Logic Pro X's Channel EQ plugin as a visual guide in this section.
Not all EQ plugins or hardware units have the same interface, but the principles are the same. Logic's Channel EQ is good to learn on as it is a good visual representation of what's happening to the frequencies of whatever sound you're EQ'ing.
First of all, we're going to look at EQ 'shapes'. The most common shapes in EQ are referred to as Bell, Shelf and Cut.
A bell shape is used for boosting or cutting certain frequencies and can have a setting called a 'Q' which basically determines how wide the bell shape is. The Q makes it possible to cut or boost either a very small frequency range, a very wide frequency range or anywhere in between. The bell shape can be seen in the image below:
A shelf EQ is for boosting or cutting at the low end (bass) and high end (treble). The width of this is usually adjustable as well. The image below shows both a high and low shelf:
Lastly, the cut is also for the high and low ends of the frequency range, but will literally cut out every frequency that it's being used on. Low cuts are also referred to as high pass filters and high cuts are also referred to as low pass filters. The following image shows both a low and high cut.
Corrective EQ usually involves cutting out unwanted frequencies that are problematic in the mix of a track.
For example, the low mid frequencies can often clash with each other causing the track to sound muddy, lacking clarity. This is due to different sounds 'fighting' for the same space in the frequency range. This is where the frequency jigsaw puzzle analogy comes in handy.
Low mid frequencies can be cut in certain sounds such as vocals to make them sound clearer.
Of course, it's good to get creative with EQ as well. Using it as an effect, much like you would with reverb or delay.
One nice example of creative EQ'ing is automating the cut shapes to sweep across the frequency range causing a filter effect.
Logic's Channel EQ also has some great presets to experiment with, such as the 'megaphone' and 'telephone' presets pictured below.
If you're interested in learning more about music production including EQ, we offer a foundation degree in Creative Music Production And Business here at CM. Check out our course page for more information.
Like most areas in music production EQ is something you'll get more familiar with, the more you do it. It really is one of the most important aspects of mixing so it is definitely worth looking at in more detail and practising it as much as you can.
It's also great for developing your ear for music production, which is a must for music producers.
The areas covered in this blog should act as a good starting point and help you to understand how EQ works, but always strive to keep developing your knowledge and mixing skills!
Another key stage in mixing is using compression to help balance and control the dynamic range of certain sounds. To gain more understanding about how to use compression in your mixes, please see our other article: A Simple Guide To Compression.