The compressor. Possibly one of the most mystical, misunderstood, and yet even simplest tools in the producer's arsenal. It has the power to improve or ruin any mix. Can you be sure you know when to draw for it? Join us for a quick tour of how, why, and when to use a compressor...
Although a compressor is a simple tool - Let's be honest here, it's essentially just an automatic volume knob - For many, it's something that causes a lot of confusion. Much of this is put about by forum users pushing forth received wisdom, and leads innocent people into some strange practises. We could write a whole book on when or when not to use a compressor, but let's look at a couple of basics.
Firstly, not everything needs compression! This might sound obvious to some, but I was recently teaching a student who, as step one when creating a new channel in his DAW, put a compressor on there. Just because, "you know, compressors are good". It's unfortunate that people end up in this mindset, as it will certainly hinder their mixdowns.
So it's very important to consider, then, exactly why you're putting that compressor on your channel. What problem are you trying to solve, or what effect are you trying to achieve? If you don't know, then it's probably best to leave it off for the time being. There's no inherent problem in not compressing things much, if at all. It's only a very recent development that we've been presented with the chance to have compressors on every channel anyway - Until a just few years back, a compressor was a hardware unit and most dance music producers would only have a couple. So they'd have to be a lot more considered about what gets compressed, and how to work with dynamic range otherwise. 
That leads onto the other point - With audio production there are many ways to skin a cat, and often a compressor won't necessarily be the easiest way to get what you want. If you have a synth or vocal line with a couple of occasional louder parts that you want to tame, it might well be easiest to just draw in a bit of volume automation at those points, rather than trying to set up attack and release times. Similarly, if you wish to tame a transient on a snare, it might be easiest to lop off the top with some subtle overdrive, which can be configured relatively easily.
In fact, one exercise which I'd recommend to anyone, would be to write a track with no compressors at all. With transient shapers, distortion, overdrive, hard-clippers, de-essers, limiters and volume automation you can achieve more or less everything that a compressor can do, and it will get you thinking more analytically about exactly what you need a compressor for in the first place.
So then - Enough of when you shouldn't be using then, what DO you need a compressor for? There are two main ways of using one (and indeed any effect) - For creative purposes, i.e. to radically change the sound to make an interesting effect, and for fixing sonic problems, or helping things sit in the mix more comfortably. Looking at the latter, a compressor is probably best used on busy tracks when automation or other solutions would be unfeasible. If you find that you can't quite seem to find the right level for a channel – too loud in parts, too quiet in others - Then it's probably a good time to reach for one. Or, if you have a buss and you want to glue the sounds together a little, by letting some smoother sounds duck under some more vibrant ones, a compressor may help here too.
A good place to start would be with the presets on your compressor. If you're new to the compression game and wish to process your drum buss, then see if you've got a 'drum buss' preset and go from there; if you don't think it's doing exactly what you want, then try tweaking some settings (more on these later). But the key things to remember are to make sure you're not making things too complicated, and that you're actually improving the situation. Be ruthless, and make good use of the "bypass" or "compare" function on your plugin. If it's not actually helping, then go back and start again!
So, these are some general tips to get you thinking - Join us next week as we go more into the specifics of ratios, thresholds, attack and release....
