The sculpting of frequency content within multiple discrete audio signals for the aggregate benefit of the overall mix, equalisation is a technique that every audio engineer must master. Here are a few pointers to get the inexperienced up and running, and give old hands some possible food for thought.

Use The Right EQ For The Job

When you reach for an EQ plugin, you should always know what it is you’re aiming to achieve with it, and, therefore, what type of EQ you need. If, for example, you’re looking to get rid of low-end rumble in a vocal, a simple high-pass filter will suffice. But if you want to get into the details of that vocal, emphasising its defining frequencies by attenuating problem areas in the signal, a parametric ought to be your weapon of choice. There’s considerable variation within each type to bear in mind, too, with vintage analogue EQ emulations generally being less surgical than modern equivalents, but desirable for their warmth and vibe, and, often, the inherent musicality of the curves they’ve been designed to facilitate.

And then there are dynamic EQs, including FabFilter Pro-Q 3 and Sonnox Oxford Dynamic EQ, which combine compression and EQ, enabling frequency-targeted gain changes to be made based on the volume level of the incoming signal; ‘smart’ EQs such as oeksound Bloom and Sound Theory Gullfoss, which literally do the hard work for you, constantly adjusting their EQ curves to optimise the spectral balance; Sound Radix Surfer EQ 2, which tracks the pitch of a monophonic signal to maintain equalisation as it rises and falls; and Eventide SplitEQ, which lets you EQ the transient and tonal components independently. As great as these things are, though, they’re not intended to be sweepingly ‘superior’ replacements for conventional EQ, and thus shouldn’t be your automatic first port of call in every frequency-shaping scenario. Again, don’t be beguiled into blindly firing up the most powerful EQ in your arsenal when all you need is an aerating high shelf.

Get To Know The Frequency Spectrum

While it’s certainly possible to EQ ‘intuitively’, starting with a flat response curve and carving away at it until you hit the result you’re after, it’s far better to understand at least roughly where you should be concentrating your efforts in order to get the sound in question where you want it to be. There are two aspects to this: knowing the frequency ranges in which the various instruments operate, and knowing what sonic effect cutting or boosting a certain range will have in general terms, regardless of the source material.

As ever, there’s no substitute for experience when it comes to learning your way around the frequency spectrum, but when you’re getting started, there’s plenty of assistance to be found online. Googling ‘EQ frequency guide’ turns up numerous informative charts and diagrams. Don’t just try to commit them to memory, though, as they’re not meant to be prescriptive: get some tracks up in your DAW and play around with the suggested settings to gain insight into their nuances and application.

Don’t Overlook The EQ In Your DAW

Before you splash out on that fancy EQ that you just heard your favourite producer uses, are you quite sure you can’t get the results you’re after using the EQ plugin(s) built into your DAW? Stock EQs have come a long way in recent years, and the likes of Logic’s Channel EQ, Cubase’s Studio EQ, Live’s EQ Eight and Pro Tools’ EQ III are more than good enough to nail any conventional frequency-shaping task, generally offering at least five bands and the gamut of filter types. DAW-based equalisers also have the added benefits of being highly optimised within the host software, of course.

Without doubt, there are plenty of third-party EQs out there that are objectively ‘better’ than those in your DAW when it comes to features, algorithmic heft, etc, but honestly, for the majority of mixing and engineering tasks, you need look no further than the EQ tools you already own.

Cut Rather Than Boost When Possible

One of the central tenets of mixing is that, when dealing with EQ, it’s better to cut than boost. With headroom being an important factor in any mix, you don’t want to risk eating into it by significantly increasing the gain of a specific frequency range within any sound, when you could, instead, reduce the gain of competing frequencies in other parts to bring out the one you’re looking to draw attention to.

Of course, this shouldn’t be taken as law, and if a boost is required, don’t be shy about applying it. Do, however, keep such gain increases as small as possible and apply them across a broad bandwidth, as sharp, heavy boosts can sound very unnatural.

Don’t EQ In Isolation…

When applying EQ to a single element within a track, while it’s perfectly fine to solo the channel occasionally to hear it on its own, most of the time it should be kept in context, as changing the frequency content of an individual sound can have a profound effect on the overall mix. For the mixing novice, this can require a degree of discipline at first, but assessing EQ tweaks in situ absolutely needs to become your norm, so step away from that solo button.

…Or For The Sake Of It

While there’s a case to be made that every sound in a mix probably should be EQ’d to some extent – primarily relating to the use of high-pass filters to remove troublesome low-frequency energy from everything that isn’t the bass or kick drum – don’t convince yourself that a particular sound should be sculpted when it doesn’t really need to be. Use your ears and judgment, and if it sounds right, it is right!

If EQ Isn’t Cutting It, Consider Re-recording

If, on the other hand, you find yourself really struggling to get a troublesome instrument sounding the way you feel it should with EQ, it might be worth biting the bullet and re-recording it. Assuming your recording setup is up to scratch, and given the power and flexibility of today’s EQ plugins, this shouldn’t happen too often and will be annoying when it does; but tracking that dodgy guitar line again never takes as long as you think it will, and you never know, you might get a better performance the second time round!

Have you got some EQ-related wisdom to impart? Speak your brains in the comments…

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