EQ: BEFORE OR AFTER COMPRESSION?
Each EQ/Comp relationship has a unique purpose and result, but interaction is the underlying principle in all of them.
“Does EQ Go Before or After Compression?”
"Yes." This is not a joke; if you were to see a normal mix session for me, you may notice that whenever there is a compressor on a track or a buss, there is probably also an EQ placed before and after the compressor.
Each eq/comp relationship serves a distinct purpose and has a different impact, but interaction is the underlying concept in all of them. A following compressor affects the sound of an eq, a followup eq affects the sound of a followup compressor, and a followup eq affects the sound of a preceding compressor.
If that seems difficult, it is, but it can be boiled down to the following 4 very basic principles. You'll start to comprehend not only when to use an eq before and/or after a compressor, but also why and (more crucially) how, if you can wrap your head around this.
• The curve of any previous eq is flattened using a compressor.
• For any eq that follows, a compressor produces additional harmonics, energy, and frequencies.
• An eq alters the strength and focal point of any compression that comes after it.
• An equalizer (EQ) partially undoes compression that came before it.
I'll give you a short exercise for each principle so you can quickly hear it in action rather than using a lot of words to describe what they sound like. There will probably be at least one that makes you have a "a-ha" moment that you can use in your own mix practice or to apply to a project you're currently working on.
A COMPRESSOR SMOOTHS OUT/FLATTENS THE CURVE OF ANY EQ THAT CAME BEFORE IT.
A vocal recording should be soloed, given a forceful 9dB boost at 1kHz, and then given 5-7dB of 10ms attack/100ms release 10:1 compression. Level-match the vocal so that it is loud enough with the compressor on and the compressor bypassed. As the compressor flattens out that harsh boost, you'll notice that the compressed vocal sounds less EQ'd.
AN EQ MODIFIES THE DEGREE AND FOCUS OF COMPRESSION THAT FOLLOWS IT.
Turn the compressor on but decrease the 9dB boost above to flat. Watch the compressor's tone and gain reduction meter. As you listen and monitor the gain reduction meter, gradually increase the equalizer's gain to 9 dB. Take note of how the EQ doesn't appear to be boosting by 9dB. Bypass the compressor at this point so you can hear what 9 dB at 1 k sounds like.
AN EQ UNDOES SOME OF THE COMPRESSION THAT CAME BEFORE IT.
A COMPRESSOR GENERATES ADDITIONAL HARMONICS, ENERGY, AND FREQUENCIES FOR AN EQ TO THEN BOOST OR CUT.
FOR THIS ONE, SET YOUR MONITORS TO VERY QUIET. Put a tone generator plugin in front of all three and turn off the EQ and compressor to create a 1k tone at -6dBFS. At the very end of the chain, add a spectrum analyzer plugin and look for the single harmonic peak at 1k. Activate the compressor now and take note of all the fresh frequencies and energy in the sound. To give an eq (and, for that matter, every other processor) more color to work with, consider how many additional tones that compressor will add to a complicated sound, much alone a mix of hundreds of complex sounds.
As you gradually learn the art of compressing for a sweeter tone and eq'ing for greater dynamic control, you may start moving beyond the obvious uses of your processors after you have a strong understanding of them and what happens when they interact. That kind of advanced engineering transforms a production from "hey, not bad" to "how in the world did they achieve that? "
WE’RE ALL REACHING FOR THAT LEVEL. GIVE IT TIME AND KEEP PRACTICING THE ABOVE, IT’LL TAKE YOU FAR IF YOU LET IT!