I am frequently asked this question, and my response is consistent "yes." If you were to see one of my mix sessions, you would notice that whenever there is a compressor on a track or a bus, there is probably also an EQ placed before and after the compressor. There are no strict rules, which is the quick and likely extremely disappointing response. Before you begin to work on your audio material, there are still some technical concerns to make. At its foundation, mixing and mastering involve the manipulation of energy. You need to control what will be audible following the mix you have in mind. 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.
What is the classic approach to this?
The traditional order of processing is equalization first, compressor second and this is for a very good reason. You might be wise to first clean up a signal if it has spectral faults like such strong resonances. That is when equalization via linear audio processing comes into play. By eliminating the harsh elements of a vocal recording, for instance, you can use an EQ to establish tonal balance. These undesirable signal energies will significantly affect your compression performance if you don't address them before using a compressor. Therefore, it is wise to use an EQ first, followed by a compressor, whenever working with audio material that has distracting signal intensities.
How a mastering engineer approaches this?
My approach to this when setting up my mastering chain is exactly the way I've always done it with my analog chain. I like to keep things in order so that it doesn't change all the time. I don't change the sound and I get a consistent master every time. If you are in the box, it's kind of the same as if you're out of the box too. You can have a mixture of the two but that doesn't answer the question. Does compression or eq come first? Well, compressors I tend to use more are for flavor, so usually the first hardware I go into is something that has tubes to warm things up to get things sounding warmer, then I go into an eq which is going to be kind of a broad eq to kind of flatten the sound out, something like a Bax EQ maybe or a Pultec, where I can just really use wide bells and lift the top or the bottom just to get some shape to the sound.
So, what I'm doing, first of all, is, I'm getting the color and shape that I want. Once I've got that basic part done, I'll go into a more detailed eq to do any specific frequency that needs taking out. After that, I'll probably go into another compressor just to kind of glue it all together to get a solid sound. I might have an eq after that to open it up again, so I might have brought it all down with a compressor and then open it up with an eq afterward. Then I might go into like a multiband if I need to, just to tighten up areas or maybe a de-esser at the top frequencies. If that has taken too much off then I'll go in with another eq to kind of counteract that.
When I say I go into this or that processor, of course, I don't do all that on every single track. You shouldn't do that on every track you master. What the track needs is the point of the matter. It doesn't matter if you've got an EQ before or after the other usually. I've got an eq after a compressor because the compressor has pushed the sound together, so I want to open that up before I go into the final limiter. Because the limiter is always at the end of the chain, I want it nice and open. I want the dynamics there because I'm hitting a limiter which is essentially a compressor right at the end. That's going to push the sound down. Before I get into that limiter I want to make sure that I've got everything nice and spiky with some eq.
So to sum it up, go into an eq to get the balance right just to get the top and the bottom frequencies to balance off, use a wide shelving eq, then go into some compressor to warm it up, just to get a more of a sound and then I'll go into another eq to strip the kind of areas that I want to do more detailed eq. And I'll go into a compressor to take all that strippiness and pull it all together. Finally, I might need to go into another eq to open it up. I hope this helps when you're mastering your music.
