When it comes time for students to mix their final class projects, a common question I hear is, “Should I put the EQ before or after the compressor? Which way is correct?” There’s not actually a right or a wrong way here. Instead, it’s about the sound that you’re going for, the sound that you hear in your head. Each position, EQ pre (before) or EQ post (after) compression produces a distinctly different sound, a different tonal quality and coloration. As a rule, using EQ in front of your compressor produces a warmer, rounder tone, while using EQ after your compressor produces a cleaner, clearer sound. So, the question you need to ask yourself for each channel in your mix is, “Do I want to EQ the compressed signal or do I want to compress the EQed signal? What sound do I want for this signal?”

I find that in most of my mixes about 80% of my EQ is post compression. I usually start with all of my channel EQ set up post compression, but in Pro Tools it’s a snap to drag and drop the EQ plug-in to a different insert slot and hear the difference. To facilitate this workflow I have my compressor plug-in inserted in slot C and my EQ plug-in inserted in slot D. If I then want to hear the EQ pre compression, I simply drag it to insert slot B. This works great even when I’ve already created my EQ curve post compression, I simply drag the EQ plug-in pre compression and Voila! I can immediately hear how my signal sounds when I’m compressing the EQed signal, versus EQing the compressed signal.

It’s also fine to insert your EQ pre and post compression. But, you should employ this technique sparingly because over doing will likely lead to an over EQed mix that sounds harsh and grating. An acceptable way to apply EQ pre and post compression would be to employ a single High-Pass EQ band pre compression, to sculpt your signal at a macro level before compression, and a multi-band parametric EQ post compression to really fine tune the sound.

EQ Pre and Post Compression

Of course, I can talk about how EQ sounds pre and post compression until I’m blue in the face. Carefully listening to the difference between the two positions is what will cement the sonic image in your mind and allow you to reach for the appropriate color in your mix. Below is a rather heavy handed EQ job pre and post compression for you to hear the difference. However, don’t just take my word for it—especially since streaming Web audio and computer speakers lack the clarity necessary to hear this level of fine sonic detail—you should also experiment with these two EQ positions in your own DAW software program in order to hear the difference on your own system.

Using EQ Effectively

Mar 31 2008

A common question that students ask is, “How do I use EQ? What’s the best way to EQ each instrument in my mix?” Unfortunately, there’s no simple answer to this question. Unlike a compressor plug-in, most EQ plug-ins don’t have presets—if only it where this simple. Instead, EQ curves vary from mix to mix, and from track to track. Even the same instrument, recorded during the same session, but in a different song, will be treated differently. This is because no one instrument is ever heard in a vacuum, and every arrangement is unique. Consequently, each mix requires its own set of individual EQ curves to make it sparkle and shine.

That said, here’s the rub. The secret to efficient EQ processing is twofold: an ability to hear the frequencies that you want to change, and a working knowledge of the EQ controls with which to do the job. Both of these orders are easily accomplished by themselves, it’s putting them together that can be challenging.

In order to accurately hear your music you must have a good monitoring system, professional studio monitors, and, preferably, more than one set of speakers. (See my earlier blog on Setting Up Multiple Monitors for Better Mixing.) Your monitors must be positioned properly in your room and your room should be tuned to achieve the best possible listening environment. (I’ll discuss how to tune your room in a future blog.) The bottom line is this, if you can’t hear what you’re working on because all you own for monitoring is a pair of headphones and computer speakers, you can’t expect to become an EQ master.

Next, you’ll need to understand all of an EQ processor’s parameters. For example, the difference between Frequency and Q controls, and when to use a high-pass filter versus a low-shelf EQ. Such details are explained very nicely in the PDF document that comes with Pro Tools 7.4, and can also be downloaded directly from the Digidesign Web site, the DigiRack Plug-Ins Guide (version “v74”). (Some versions of the DigiRack Plug-Ins Guide without the “v74” appear to be missing the DigiRack EQ plug-in chapter.) Consequently, I won’t waste space trying to explain all of these parameters here, just read the manual.

Now, let’s jump to the chase, how to go about finding a particular set of frequencies in your signal that you can hear needs help (and you can hear this because you have properly set up monitors and a fine listening environment). My favorite technique is to insert a parametric EQ, and to use it like an EQ magnifying glass in order to find my troublesome frequencies. This is a technique that has been in use ever since the invention of parametric EQ, so I’m sure it has several other names, but I call it the “magnifying EQ trick.” Here’s a video I made on how the process works.