Practical & Effective EQ Use

Equalization is perhaps the most-used processing tool in audio production.With the use of compression (read my Practical & Effective Compression Use article), it’s also perhaps one of the most improperly applied ones in an engineer’s arsenal as well.

Since equalizers and equalization seems to be so self-explanatory, understanding it past the mechanical functions of and differences between a graphic EQ or a parametric EQ may seem irrelevant: If I want something brighter, I simply reach for a shelving filter at 8K and boost it, right?

Little could be further from the truth!

Just as our ears are more sensitive to frequencies in the midrange to upper midrange (See Dithering elsewhere on this blog), our ears are actually more “tuned” to hearing energy reductions in a frequency range rather than boosts. As a result, boosting frequencies automatically stand out and attract more attention than frequency cuts. For example, it would take a boost of 9db in any particular frequency range to equal a cut of only 6db in that same range.

So, although it may seem backwards, and especially when trying to shape sounds rather than simply using EQ clinically to filter out unwanted frequencies, one can often get better results when first considering a reduction of the unwanted frequencies, rather than simply boosting the wanted frequency.

In other words, if I was trying to get more clarity out of a piano, I may instinctively reach for that 8K shelf and crank it up, when in actuality, reducing the frequencies from 8K downward may actually get me a sound that is more transparent, and with more clarity and definition as well!

Using this technique can have many additional benefits as well, such as automatically not attenuating any frequency spikes that might not be apparent to us, causing problems later on, in addition to freeing up some space in the mix, allowing us to raise overall levels of individual tracks rather than constantly pulling faders back.

Furthermore, and to me, something that can make the most difference of all, is when surrounding frequencies are cut rather than boosted, causes a perceived increase in harmonics. Harmonics are part of that elusive and mysterious aspect of sound that digital is perceived as having a terrible time of reproducing. And actually, one of the reasons I absolutely adore my Avedis MA5’s is because it has this magical button on it that says “28K” on it. Although we’re not supposed to be able to hear anything above 20K, it increases the harmonics of audio material, and can often create far more than a subtle difference in sound and clarity of a sound.

So, whether it’s a parametric a graphic EQ, maybe try to come at your equalization from the opposite angle (especially, in my opinion when it comes to mastering) next time you have the opportunity to do so. With a digital workstation it can be as simple as putting the exact same EQ plug-in on a track, and on one plug-in, boosting the frequency you want to add to the sound, and an the other; cutting all the other frequencies.

To me, this can be most easily apparent in the low end (such as bass guitars or kick drums), and you may find that your boosted low end fix might sound muddy and lack clarity, where your cutting of the surrounding frequencies actually (once you increase the gain to match the energy output of the boosted EQ) increases clarity, gives you more punch, and simply sounds better to your ear.

And this is another aspect of cutting rather than boosting when it comes to EQ. Simple cuts, especially when it comes to broad coloration of any particular sound, can have huge benefits later on in the mixing and mastering process. If we take the example of the kick drum or the bass above, cutting the surrounding frequencies, especially when we need to cut less than we would have to conversely boost, can reduce the overall energy level of a mix! – So, when you’re trying to go for that “fat” or “huge” sound, you may find that if you compare a mix full of boosts to a mix full of cuts, that at the same exact meter reading, that your “cut” mix will not only sound clearer, it may actually sound 1-3 db louder than your other mix. This can become even more apparent when it comes time to master, and compressors or brick wall limiters are applied to the overall mix; there will be a smoother overall curve to work with, further increasing the amount you may be able to boost the perceived level of your mix.

If there are fewer peaks, the limiter will allow you to get even more gain out of your material before any noticeable compression, distortion, or artifacts. Even when not going for “maximum volume”, the effect that this can have on the overall sound of your mix can be astonishing. Try it sometime, and let me know what happens by posting any comments or questions you have below.

As an added note; something I found fascinating was the actual mathematics between the SSL sound and the Neve sound when it comes to equalization. If you’re interested in sculpting sounds, whether when tracking, mixing or mastering, my article called “Neve & SSL EQ De-Mystified” may offer some surprising insight into making your mixes sound better than you thought possible, without having to spend thousands on outboard EQ’s.

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