Fix Common Mix Problems with EQ

In the never-ending quest for the perfect mix, EQ is one of the oldest tools we have, and still one of the most powerful. Used in moderation, EQ can add clarity and definition to a crowded soundscape. Used with precision, it can remove offending sounds we wish we hadn’t captured. As a strategic tool, a bit of EQ can make all the difference needed to separate dueling guitars, scoop the mud from your drums or make a vocal shine.

But EQ is often misused and misunderstood, usually as part of an attempt to fix a poor recording. The most basic recording tenet still applies: garbage in equals garbage out. A little EQ is great for helping make a good track sound better, but no amount of EQ will make a bad track sound good. The best mix starts with the best recording, so try to capture the best sound you can to begin with.

Your ears are the bottom line when it comes to applying EQ. We can talk about a few general principles, but every instrument has its own unique characteristics and timbre, and will react differently to boosting or cutting specific frequencies. So take these and all suggestions with a grain of salt; use them as a starting point, but make your decisions based on what sounds good.

Take it Away Now

EQs come in all shapes and sizes, but they generally control three parameters: frequency selection, gain or cut, and bandwidth or Q. For mixdown purposes, a multiband parametric EQ like the Precision EQ or Cambridge EQ can be great for focusing on specific frequencies, allowing you to really sculpt the sound of an instrument.

When it comes to EQing, less truly is more, and it’s better to take than to give. Most people have a tendency to make an instrument stand out by boosting frequencies, but the cumulative results can be dangerous. Adding just 2 dB of gain to two instruments means that when they excite the same frequencies (and they will), you’ve got 4 dB of gain. Add too much EQ and your mix can easily turn to mud. It’s often a better idea to try attenuating those same frequencies in other instruments instead.

Another good reason to minimize your use of additive EQ: Although cutting frequencies is a passive process, adding gain makes your EQ function as a preamp within the signal flow. Adding any preamp means adding noise and distortion, and the preamps in most EQ circuitry are less than optimal.

All those arguments aside, sometimes it’s simply more effective to boost one element of the mix, rather than rolling off dozens of others. Once again, the operative word here is moderation. A little boost of 1 or 2 dB goes a long way.

EQing Drums–Making the Kit Fit

If your mix includes drums, it’s a good bet you’ll spend more time EQing them than anything else. Because drums cover such a wide tonal range, there’s plenty of other stuff in the mix competing for those frequencies. Kick and snare in particular tend to be prominent parts of the song’s fabric, and most engineers revisit them often as they build their mix.

EQ can be a good solution for less-than-optimal drum tracks, but it’s far from a panacea. Because every drum track also contains leakage from another mic, boosting a frequency on one track can also bring up the off-axis sounds of adjacent mics, potentially creating more problems than it solves.

For a dull-sounding kick drum, adding a slight boost anywhere around 80 to 120 Hz will produce more boom and a more rounded sound. Adding a tiny bit of 500 Hz can bring out the “click” of the beater hitting the drum head, and is usually helpful in preventing the kick from disappearing once your track gets to the inevitable low-fi MP3 version.

Snares come in such a wide range of sizes and materials, it’s a bit tough to generalize about frequencies. But the sound of the snare wires rattling lives in the 5- to 10kHz range, and a bit of gain there is great for brightening up a dull snare. If you’re plagued with a boxy sounding snare, try rolling off a bit of 300 through 800 Hz.

With toms, a common mistake is to try boosting low end to make them stand out. Sure, adding a couple of dB at 100 Hz will increase their power, but at the expense of muddying the mix. A better strategy for perking up those tom fills is to leave the bottom end alone and add a tiny bit of 5 kHz to bring out the attack. And as with the snare, play around with rolling off that same 300 through 900 Hz range to eliminate boxiness.

Almost every tom has a resonant ring, and some can be problematic. Although your first impulse might be to reach for a noise gate, a bit of correction might do the trick and sound more natural. Using a multiband EQ like the Cambridge, select a narrow Q and boost the gain as you sweep the midrange band. When you locate the offending frequency, apply a few dB worth of cut to make it go away.

Overhead mics can be a mixed blessing. Their position and relative distance from the kit make them great for adding air and ambience, but loud cymbals can overpower the mix. Try adding a bit of 10 kHz to brighten the track, and then backing off the overall level to get the air without too much metal.

Since bass and kick occupy the same frequency range and (hopefully) work together, it’s usually good to use EQ to differentiate them in the mix. Pick one as the rounder, bottom-y sound and make the other a bit more punchy; which is which will be dictated by the song.

If you’re working with a bass track that was recorded direct, chances are it’s a bit flat and nondescript compared with a miked bass amp. Ultimately though, that flatness will make EQing the DI track far easier, since there’s less coloration to begin with.

Like the kick drum, boosting the 80 to 120 Hz range on an electric bass will add roundness and bottom end. To add presence and attack, go for a slightly higher range than with the kick, around 1 kHz. Don’t add too much or you’ll bring out the finger noise as well.

Making Space for Guitars

Guitars are among the most versatile instruments, and that same versatility can make them a real challenge. With electric guitars, if you’re fortunate to have a player who knows their amp and sound, your best bet is to change as little as possible.

If you’ve got two rhythm-guitar parts going, a bit of EQ can help distinguish one from the other. Try a slight boost at around 100 Hz on one to bring up the lower mids (with perhaps a corresponding cut on the other guitar). Experiment with higher frequencies on the second part — boosting different frequencies between about 750 Hz and 10 kHz will each bring out a different type of sparkle. Scooping out a bit of 250 to 500 Hz can help eliminate some harshness and woofiness.

Acoustic guitar is a very different animal. Each has its own unique tone and timbre, and much will depend on the sound of the room, the mics you’ve used, and where you’ve placed them. A mic too close to the sound hole will deliver a boomy sound; a slight cut at 100 Hz can help. Close miking can also pick up some boxiness from the wood’s resonance, especially around the midrange. Try dropping a bit of the 300 to 400 Hz range. And of course, bring out the shimmer and strumming sound by boosting the upper ranges, from 750 Hz up to around 10 kHz.

Listen Before You Look

One last point. Advice is great, but there are no hard and fast rules except one: Use your ears. It’s all about how it sounds, so close your eyes and listen. Adjust your EQ, then listen again. Listen to your changes in the context of the whole mix, not just soloed.

Don’t depend on gauges and readouts, and don’t boost a certain frequency on an instrument because you read that someone else always does. Every instrument is different, every room sounds different, and what worked for one person on one recording won’t give you the same results.