Can some mix engineer or producer help me understand what compression is? I understand what threshold is. I understand what ratio is. I understand all of that, but I don’t know why. Why is compression?
Well, yes and no. I’m Nathan. I run an audio school where we teach music and production without using recordings. I’ve personally taught hundreds, if not thousands of people, how to use a compressor. And there always comes a time when the question becomes not what does a compressor do, but why? Why are we compressing everything? It’s a legitimate question. If you look at a mix from a professional, it’s not uncommon to see a compressor on most, maybe all of the channels, which leads a lot of you to believe that there’s this one thing that you’re supposed to do to everything. That’s where you’re wrong.
Just like an EQ, a compressor is a device whose function is selective leveling. You can raise or lower the level of a track with a fader. An EQ can raise or lower those levels just for the high or the low. And a compressor is less about what level is changing and more about when.
To your way of thinking, there is one reason that you would put an EQ on a track. But that’s not the case. Just like the EQ might impart a change to the lows, the mids, or the highs, a compressor isn’t a one-trick pony. You’re not seeing a compressor on every track because it’s solving the same problem. It’s the same tool solving a whole variety of problems.
A compressor can make things quieter, reduce the dynamic range. It can make things louder. It can increase the dynamic range. And when you understand that, you’ll stop fruitlessly searching for the common thing it’s doing to every track, and you’ll start to think about the unique problems that it’s potentially solving on each of those tracks. And I’d argue that if you can’t identify what you want to change or what problem you’re solving, maybe you shouldn’t be using a compressor in the first place, because when you need it, you’re going to know why.
