Getting your head around EQ should be a priority for everyone learning to mix, so I have put together this blog, sharing some thoughts, tip and practices to hopefully give people a bit of a leg up.

So what is EQ?

Audio Equalisation is all about adjusting the balance of frequencies in any composition of sound. Originally EQ was developed as a corrective and mitigating process – due to the limitations and idiosyncrasies of equipment used in the early days that was not as accurate and transparent as the kit we enjoy today. So back then you were often dealing with having to make changes to the frequency balance in order to iron out problems with a recording just to get it sounding right. This is where the term equaliser has its roots, as it was the piece of kit which allowed you to change the audio you hear at the output so it is equal to the sound which you heard at input.

These early pieces of kit were mostly analogue and often had a certain sound all of their own, which in turn lead to more creative use of EQ, with people using them to sweeten and add to a sound the tell-tale signature you get from the analogue equipment. This use means that obviously the input is no longer equal to the output, although the output is better for your musical ideals. In modern gear, even plugins, the same can be said to be true, with a lot of modern plug-ins now looking to emulate the sound of the previous generations of hardware, with varying degrees of success. More recently the word Equalisation is used as a cover-all term for the many diverse modern techniques of using the EQ. More than any other tool in your arsenal the EQ is one of the most powerful, most important, and easiest to usewrong.

When it comes to EQ it is as important to know what your piece of kit / plug-in is good at, just as much as it is to use it correctly – I will illustrate this in more detail below.

EQ to correct and balance a sound

Beyond working with your composition so it sounds correct or equalised in the traditional term, using the EQ in a surgical manner to remove unwanted audio elements and problems is vital if you’re looking for a good mix-down. Getting sounds within a mix to mesh or gel together is an art-form in itself, part of that process is controlling the shape the frequency content of each sound – not in isolation, but in the context of your whole mix. By cutting small amounts away from specific frequencies in each sound, and getting rid of unwanted parts of the sound with filters, for instance: a recorded hi-hat where any low end noise is completely unwanted, you are well on your way to a mix that’s easy on the ear. But how to you know where, or how much to cut, and what about boosting?

EQ to enhance a sound

I mentioned above how use of EQ nowadays has gone far beyond its’ originally intentioned use, due to the equipment itself and our own ingenuity. There are many types of EQ, and with all things audio everything has it’s own sound and we have in our wisdom often found good uses for that inbuilt variety. If you look at some of the EQs in famous analogue desks and high-end outboard, there is a lot of sought after loveliness (for want of a better word) inherent to different EQ’s. Even if on the surface they portend to do exactly the same job, sometimes you might want to boost the high-end to add air to a recording, or warm up the bottom end a little. Equipment that is designed to be precise and sterile is not always the best for this kind of work and it is important to spend the time listening to your equipment and learning it, pushing the limits of what you use and seeing what you like best in certain situations. You will soon begin to get an idea of what you like best if you put the time in. In a pretty rule-less area of techniques, where you should be driven solely by what sounds good, there are a few guidelines which can be applied to most situations to help you achieve a decent result. When working to enhance your sound, make sure you work sparingly and don’t use too much gain. If you bring out the high end make sure the sound still sounds balanced, make sure it doesn’t get harsh or aggressive, as with all things EQ – subtlety is the key. The more respectful the changes you make the better they will sound, and small changes have a bigger impact on a well balanced mix, but as with all guidelines feel free to ignore… IF it sounds good in so doing.

To boost? Or cut? Does it really matter?

So what is the big difference between cutting and boosting? Depending on the design of your EQ there will always be some audible effect of the actions you take on top of the desired frequency changes – you could call this distortion. Depending on the equipment you’re using this can be entirely desirable and part of the unique flavour you are after, but when working on more corrective EQ work that is often not the case. The best way to look at a Boost is as if you are Cutting every other frequency, so if you think that through you are basically thinning out the sound, as the frequency you boost will become more apparent but ONLY that frequency. That will also be the frequency on which you may experience your unwanted distortion or phase problems, and it will be more prominent than the others now you have boosted it.

Compare that to a cut, a simple cut to take out a problem frequency that’s clashing: not only will it not have such a big change on the balance of the sound, as you are only lowering one area of the frequency but any audio issues caused from the change will be LOWER in the mix than the rest of the body of sound. So the impact on your audio is much less drastic. With all that said, some EQ just sound beautiful boosting, and the distortion they impart can really add to your production so…. I repeat it is so important to be fully aware of the kind of EQ you are using for a certain job, a cheap VST EQ from the 90’s ain’t going to sound any good at boosting your highs to sweeten a mix.

As a rule of thumb, you want to be looking to keep your surgical EQ narrow and effect specific frequencies you have decided are an issue. Keep a narrow Q so you’re acting on a precise area and don’t go overboard on the gain. When you’re looking to boost, or sweeten a sound make sure you are using an EQ that sounds good; in the low frequencies use a narrow Q and in the high keep the Q wide, this way changes will sound smooth all over, and don’t boost by too much with any piece of kit. Unwanted / wanted effects get more prominent and less wanted the more you push it.

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What are we trying to achieve with EQ, how to learn to know the desired outcome

First and foremost, with a mix-down you’re looking for clarity and balance, musicality and a sense of openness in the way the sound is coming out of the speakers. Don’t look to make your mix exciting with EQ, or be overly emotional in this kind of work as it is a big mistake; you won’t get a big huge phat club-shattering bottom end by boosting 60hz. The frame of mind you need to be in is listening for balance, where each sound has its own space to reside in without anything encroaching or interfering with it. Listen to some of your favourite (well produced) music. Try and get used to hearing the distribution and level balance of the track, notice that it’s often the case that the track has an amazing top end, not because it has a lot of it… but because you can hear it with absolute clarity and it’s balanced well in terms of the lows and mids. Or, if a track appears to have a massive low end, it’s often because you can hear it clearly and it is well-defined and nothing is working against it to muffle it or slow it down. Within a well-balanced mix-down, where each sound is clear to the listener, there is plenty of scope for show-casing certain sounds through your arrangement and relying on the quality of the source sound itself to do the work for you.

Identifying and Removing Booms, Resonances & Frequency clashes from a mix

So your bottoms a muddy mess, what to do? Well there are a few things to look for here: in the lowest frequency, sounds take up a lot more space, so you’re often more restricted in what you can actually fit down there. This can cause you problems when bedding your kick and your bass, or, if you have not got rid of some boom or noise in the low end from one of your other parts. So the first step is listen and eliminate things that are not the problem, a good technique if you are struggling is to mute tracks one by one, until the problem disappears. Clarity is what you’re listening for at this moment. Keep muting and listening until you find the tracks that are causing the problem. Let’s say the issue turned out to be a clash between your bass and your kick: this is a very common case, these two instruments can operate in very similar frequency ranges. Sometimes people stick to simple rules when working down low, for instance if you have a deep bass your kick has to have less bass or if you have a big kick, your bass has to be higher up. Let’s propose in this case that’s not an option, and that side-chaining is not an option either (because it’s a lazy fix for this and it sounds poop). At this point, experienced people can use their ears and work the EQ to find the specific frequency that is clashing, but that’s something that will come to you with practice. In the meantime I heartily recommend picking up a good Analyser like Voxengos SPAN – it’s never good to rely totally on tools like this but while you’re learning it can be an essential aid. I will stress the point that as always it’s important to make the final decision naturally using your ears … ask yourself “does it sound good?”

You can download SPAN here, and set your preset spectrum mode to be a bit more like the picture above, which is really good for showing you the frequency moving in context. I always found the stock pre-sets were a little disconnected from what you’re hearing. As long as you’re not running with a crazy latency this can be really good for many issues – for example spotting peaks in the frequency on your kick that are clashing with other sounds, spotting resonances or movement in the sounds which are out-of-time with the flow of the track which could be a resonance or some noise you missed when cleaning up the part.

Ok, so lets say we found a little resonant peak at 95hz – this only happens when the bass and the kick play simultaneously as their frequency ranges cross over around there. At this stage you have a few choices: you need to think what is most important to the low end of your song; 95hz is an important frequency for the thud in your kick drum, this is where a lot of the power will come through to the listener or in a club, depending on the type of kick you’re using of course. Listening to the kick you’re using here and experimenting by cutting this frequency in isolation, this will tell you how important that frequency is to the sound of your kick. The way you should be thinking here is: you want to be taking away the least musically important frequency in either the kick or the bass. Which sound falls flat when it loses some 95hz? In this case the bass has a lot of harmonics so it still sounds great without a little 95hz, so making a small narrow Q 6db cut there was enough to clear room for the kick drum to cut through nicely. Although in the case 6db was just a little too much on the bass taking away from its’ sound in the mix, you do have a few options.

A good technique in situations like this, is to follow the rule that the smaller the change you make to the EQ the better it will sound, so instead of making a 6db cut @ 95hz we can make a 3db cut and make a small boost 1-2db on the kick drum at the same frequency, just to balance it out. Let your ears be the final judge bearing in mind we have discussed the difference between cuts and boosts, maybe you would want to use different EQs for each action?

EQ and OTHER FX, important notes on how the interaction changes if the EQ is before or after

In a previous blog I talked about the importance of proper gain staging, and how to apply that inside your DAW as well as on your analogue desk. Part of gain staging is thinking about how your signal chain is constructed and this same kind of thinking that could be applied to when and where your EQ is in the scope of things. That is important because having your EQ first and having it last in a chain of effects can have dramatically different consequences. For example, let’s say you have a Kick drum chain that’s comprised of EQ, Compressor, Distortion in that order. You have it all set nicely, but you realise there’s a little too much bottom end on your kick, so you reach for the EQ take out 2db, then you find that the change seems a bit more drastic that you’d imagined, the 2db off the bottom end means you’re not hitting the compressor as much as the low frequency content of a sound which will make up the larger part of the level of the track, and the compressor acts upon a level threshold so you will also have to change the settings on that to compensate. Not only that but the distortion is behaving differently now as you had it nicely balanced at the point where things get thicker and more interesting, and suddenly you’re no longer there. It is these un-intended consequences which you need to keep track of, that doesn’t mean you can’t use and EQ before the compressor or any other piece of equipment, but there will always be consequences downstream from it. It would be foolish to say always put your EQ last in the chain, but do always make a mental check of where the EQ is and sometimes you may want to use another EQ after it to make any tonal changes.

How to arrange your mix, and sculpt holes in the sound-scape for important elements to inhabit

A lot of your work with EQ can be done before you actually touch one; the way you compose and arrange your song has the greatest impact on what mix work will need to be done afterwards. It’s strange to say, but this technique and way of thinking can often be overlooked with the equipment to do the remedial work being so readily available. If you spend the time to pick and position the right elements at the right time, you will need to do less EQ down the line, and the sound will tend to be 100% better. If you work towards having a kick that sits nicely alongside your bass to start with, or if you write the notes of your bass so its’ frequency content doesn’t get too close to the kick, there will be benefits. If, during your arrangement, you have 2 parts which sound great but clash a little when played together – do they really need to be in at the same time? Or can you arrange it so they play at different times? If you are truly happy with the balance and sound of your mix, it’s thinking like this which can often provide the best solution to keeping that great sound. If you know you have a stand out vocal, why don’t you pick your other sounds to leave room for it.

Ways to practice

So how do you get good at this game? Well it’s quite simple really, just keep doing it. Think about it in the ways I have outlined and keep going at it until eventually things start to become second-nature, and by just plugging away at it, making notes and remembering what seems to work well for you, things will get easier every day. One great way to train yourself to hear and understand a well-balanced mix of frequency more effectively is… listen, listen to well produced music as much as you can, get a glass of wine and just listen for the evening. Really listen and think about the way the sound comes out of your speakers, learn what a balanced mix sounds like from your system, in your room. You will find that over time / by taking the time to just listen and think, you will start to automatically know what a good mix sounds like. When you’re working on your own music you will instantly hear a problem that’s pushing your track out of the perfect mix you have in your mind.


EQ Cheat Sheet

I have started to put together a little EQ cheat sheet for you guys, there are quite a few on the net but I have always found they never seem to be based around House or Club music, and are often full of very helpful frequency advice for Contra Bass Bassoons and Clarinets, what I have tried to do here is to bring some more relevant information, this is a work in progress lets called this version 0.1. So expect me to be updating this making it more accurate and adding more useful information as time goes by.