5 Tips for Using Multiple EQs When Mixing Audio

We have previously provided tips for using multiple reverbs in a mix, but what about multiple EQs? Are there benefits to doing this? Yes! In this article, we’ll detail five EQ tips for sculpting a signal with more than one EQ. 

1. Boost, then cut (or vice-versa) 

The common engineer saying, “boost, then cut”, refers to making individual adjustments within a single EQ. This same concept can be applied when using two EQs—one to remove sour frequencies and another to boost sweet ones. On vocals, guitars, and other instruments with large frequency bandwidth this is particularly useful. You may want to use a surgical, transparent EQ for subtractive purposes and something with more character when adding to the signal. On top of looking and feeling more organized, you can hone in on the frequencies that matter most and sculpt a more precise sound. 

The opposite is also true—after a significant boost on an instrument, your attention may be called to certain resonant peaks that weren’t noticeable in the signal’s original state. If you used a hardware emulation EQ for the boost, you will certainly get the color you want, but not necessarily the controls to pinpoint problematic frequencies.

A more precise, clean EQ, like the one in Neutron, is better equipped for these tasks, offering narrow equalization options and dynamic control over signal content. Used together, these two types of EQ can give you a great, modern mix. 

2. Use a second EQ to shape processing 

Before we send a sound through a tone-altering effects processor like distortion, we often use an EQ to remove the parts of the signal we don’t want to be amplified or drive the ones we do. It is equally useful to employ an EQ after this kind of processing to further shape the signal, and, if necessary, attenuate any harshness introduced. 

This concept is built into the design of iZotope’s distortion plug-in Trash. By default, the signal chain places an EQ on either side of the distortion module, but you can also modify this order to better suit your mix or create some unusual effects.

You may want to use dual EQs with ambience effects too. Though I prefer to work with reverbs and delays that include EQs to filter out low end frequencies, this isn’t always the case, and placing a subtle low-pass filter after the fact can prevent cloudy buildups. A bump around 10 or 12 kHz can also bring out a little sparkle in the highs.  

3. Try multiple EQs for tone 

Instead of using a single EQ for a considerable high shelf boost, try a few smaller shelves across stylistically different plug-ins. By combining the characteristics of each, you get something similar to the effect of a signal passing through various hardware components that alter its harmonics. The sound is brighter, but it doesn’t feel like EQ is responsible, and there is a subtle depth that wasn’t there before. 

You’ll need some headphones or monitors to hear the difference in the following audio example. The drums in the first part have a single shelf starting at around 3 kHz, and the second drum part has three EQs—one starting at 3 kHz, another at 5 kHz, and a final at 10 kHz. Notice how the upper-midrange is more excited (especially on the snare) and the groove is tighter. This is one way to add interest to drum loops and other pre-packaged sounds. 

Big note that caution and nuance is the name of the game here. If you shelve everything in your mix, the brightness you originally sought out will be much closer to brittle. Only a few elements need to be bright for an entire track to sound this way. 

4. Don’t skimp on the submix

It's common practice to group similar-sounding tracks together in a submix, an auxiliary track where you apply processing to them. In a busy mix, this is a fine spot for some extra sculpting with EQ to achieve a sense of balance and carry out creative automation. 

In the first scenario, you might want to use a dynamic EQ to help carve out space for each drum sound, even if they’ve already been altered at the track level. If the snare frequencies are masking the kick drum, a cut to duck them whenever the kick hits might do the trick. An EQ can also be used here to reduce masking between submixes—if your synths overlap with the guitars, it can be simpler to rectify the issue at the macro level instead of A/B-ing multiple tracks and making tiny adjustments to each.   

The second scenario is all about imagination. With the option to control many tracks from a single plug-in, you can automate some dramatic filter sweeps that signal a buildup or breakdown. Adding air to vocals at a particular high point of a song or even burying certain words is worth trying out too. 

5. Don’t second guess it 

While a more technical explanation may exist, sometimes it just sounds better to use multiple EQs. If the settings you dialed in on one EQ sound great and you don’t want to alter this, there’s nothing stopping you (except CPU power if you’re short) from adding another for the final touches. 

You may even arrive at a multiple-EQ situation by happy accident. Maybe a second EQ mistakenly copied to the wrong track in your session actually improves the sound. Or when turning back on a forgotten, bypassed EQ, you find it adds a surprising warmth to the mix, despite the filters already employed. I try not to question these moments much and just roll with it. 

Conclusion 

There are other scenarios where having multiple EQs working together will benefit your mix. As you well know, this changes from session to session and what you did yesterday won’t necessarily work today. Luckily, EQ is one of the simpler tools to experiment with, so I encourage you to chuck them at your insert to discover new ways to use them.