Equalisation is one of the most important parts of the mixing and mastering process, but what if you’re a guitarist trying to mix and master a track by yourself? By understanding what sounds make up a guitar strum or picked note, it becomes easier to learn the basic principles of EQ which can be applied to all parts of a track – whether a heavy riff, a lead line, or some acoustic fingerpicking for an indie ballad.
Know the ins and outs of what makes up sound
A note on any instrument is made of the pure tone itself as well as undertones and overtones. You may know these from guitar techniques such as natural and artificial harmonics. However, beyond this, knowledge of the frequencies which make up sound in general is the first stage to understanding how EQ works, as well as its purpose in a mix, and therefore how it is applied specifically to guitar.
The spectrum of sound which is audible to the human ear can be divided up into different sections called bandwidths. You may have heard mix engineers talk about sub bass, bass, or use terms like ‘mids’ or ‘high mids’. These all refer to different frequencies of sound, whereas bandwidths are the groups themselves, often as they show up on an EQ plugin – a range of frequencies between two different set points on the spectrum of sound. Below is a rough guide to how audible sound can be divided up and how this shows up on a typical EQ plugin such as the default which comes with Logic X Pro.
Below 50 Hz – sub bass
50–150 Hz – bass
150–200 Hz – low mids
200-800 Hz – mids
800-2k Hz – mids to high mids
2k-5k Hz – high frequency, verging into noise and overtones (think a hi hat or cymbal crash)
5k-20k Hz – noise
Understand how EQ affects guitar in your track
Electric guitars – specifically rhythm guitars – are going to hover around the 200-500 Hz mark in terms of the main note – low enough in the mix to bulk it out and support a soaring vocal or guitar solo. Knowing this means that you can focus on these bandwidths while understanding that anything significant which is much lower or much higher could potentially be room noise, noise from outside the studio, or other unwanted sound.
Things can get confusing when you realise with any given instrument, a note can span the whole range of frequencies, including those at the extreme high and low ends of the spectrum, which often give it it’s fullness and richness. Another example would be sound at 2-5 KHz, which is often called ‘presence’ and adds brightness to the sound. These extra frequencies are the ones you are generally removing when EQing. For example, removing the lower frequencies from your lead guitar can prevent them clashing with other instruments which sit lower in the mix and giving the track overall a muddy sound where nothing stands out clearly. Essentially, EQ is all about understanding where instruments naturally sit, and altering other frequencies to carve out space for them in these places in relation to other instruments.
For guitar solos and harmonies, you may be going into the range of anything from 500-800 Hz +. However, the most important thing to remember is that when EQing, you are separating instruments, so they stand out cleanly in the mix, and these bandwidths and the way they are commonly divided are a useful guide as opposed to hard and fast rules. The main point of EQ is to clean up unwanted frequencies surrounding the main tones, meaning that each instrument is more distinct on its own – as well as boosting frequencies which you want more of, such as if a guitar low in the mix is lacking impact, at which stage it can be given more presence to make the sound brighter.
Learn how EQ works with multiple guitars
Separating your rhythm and lead lines can be relatively straightforward, but what if you wanted to double track a guitar or add some subtle harmonies over your main riff? The same principle as above follows – find where your instrument sits naturally in the mix and see where some of the frequencies which make up the spectrum of its sound may be clashing with other instruments. By removing the lower frequencies from your high guitar harmony, you will not only prevent muddiness but also give more space to your lower riff.
When EQing, rhythm and lead guitars much be treated separately not only due to generally occupying different bandwidths but also due to having different purposes within an overall track. Higher sounds tend to pop out of the mix more than lower sounds, meaning that your guitar solo may not need equalising as much as a groove or riff might do, as it stands out already, but could benefit from lower frequencies being removed so that the chord progression could be heard. On the other hand, rhythm guitars can benefit from being more aggressively equalised with the higher and lower frequencies around them being cut more dramatically so the sound sits cleanly, especially in relation to other instruments around the same bandwidth such as bass and drums.
Understand EQ with other instruments such as bass and drums
Another thing to bear in mind is that different instruments bring different things to the EQ spectrum. A bass isn’t going to bring as much to the high end of the spectrum, but a full set of drums generally adds noise in terms of echoes, overtones, and undertones to all parts of the EQ spectrum due to the different parts of the kit ranging from high cymbals to the low kick drum. Guitars tend to sit somewhere in the middle of these two extremes but can sometimes be particularly sensitive to room and outside noise.
Overall, EQ may use different skills than simply playing guitar, but it is nevertheless one of the most powerful tools you can have in your arsenal – not just in terms of creating a fantastic track but also in honing you’re playing and taking it to the next level. By getting a better idea of what your lead lines and riffs are like in the context of not only other instruments but also how they are affected by the mixing process, you can gain mastery over your sound when working both alone and with a professional producer simply by understanding some of these basic EQ principles.