Behind The Mix - Advanced CompressionSeptember 02, 2012
Compression is one of if not the most used effect in today's music, but it is also the most mis-understood. We won't be covering how to use a compressor or even understanding the basics of compression. I am going to assume that you have a clear understanding of how to use a compressor for this article. If you don't or you find that you need a refresher on the subject than you can take a look at this article that I wrote on the basics of compression before you read about these advance techniques.
This article will cover the following compression techniques:
New York Compression
Side Chain Compression
First let me say that it is important to work with tools you are familiar with for these advance methods. Different plug-ins will give you slightly different responses and their own flavors when using them and for this reason it is important to experiment with different plugins and see which ones you like to use and which ones that you may not want to really use too much. There are lots of compression plugins out there freebies and paid ones so grab some, experiment and see which ones you like to use for the type of compression that you want to use.
PARALLEL COMPRESSION AKA NEW YORK COMPRESSION
Parallel compression is really a quite simple concept and with today's DAW's it is also quite easy to set up. Parallel compression is done by taking a sound signal and playing it dry. Next you send that signal through a compressor using very heavy compression settings. Then you take that heavily compressed signal and mix it back in with the original dry signal. You would typically want to use this type compression when you want to not reduce the peaks of a sound to bring up the overall levels. Or you are wanting to give you sound some impact but you don't want to kill the dynamics. Now how much you mix back in really depends on the track, what you are trying to achieve and the type of sounds that you are working with. This is very much a personal taste thing and there aren't really any pre-setting to give you. Trust you ears to get what you like when it is all said and done.
This works on a lot of different sounds, but I use it a lot of drums. This type of compression allows you to give your drums some impact but at the same time you don't lose your transients in the process.
With Serial Compression you will be using two compressors on the sound signal. Some say that this method is similar to parallel compression but really it is quite different. With serial compression you are using two different compressors together or in a series. These two different compressors are usually addressing two different issues. For example one compressor could be addressing the peaks whereas the other compressor may be addressing the rest of the signal. Like with most things in audio there are no rules here, but this is the way most engineers use serial compression. The key here is to use two different types of compressors for this technique (you don't have to but I have been more successful with this technique by doing so). So for example you might want to use this technique on a vocal. You could use a compressor like a VCA first to tackle your peaks, followed by a compressor that works slower like an optical for the more quieter parts. With the optical working on the rest of the vocal signal the end result of using both is usually something quite enjoyable when done correctly and will really get your vocals to fit in the mix better.
Serial compression can really give you some great results that you won't achieve from just one compressor.
The concept of multiband compression in my opinion is more of an effect than it is a method of compression. When you are applying multiband compression it is applied with a multiband compressor. A multiband compressor is nothing more than a compressor that is split into several frequencies bands. This allows you to apply compression to specific frequency ranges. This is great for tackling problem frequencies that may have trouble coming through the whole mix. Or the problem could be that a frequency is poking out too far in a mix and needs to be tamed.
A good multiband compressor is a must have in the studio. Sometimes using a standard compressor on a large mix or complex mixes will quickly lead to issues with pumping. By using a multiband compressor this is no longer a problem.
This type of compression is often used in dance music against a kick drum and gives a nice pumping sound. Of course you could use this type of compression on lots of other things besides drums. What side chain compression is really about is using the signal level of something else to influence what you compressing. See when you use a sidechain compressor it is getting a signal from another sound within your track to control when it should and should not be compressing the signal you are currently working with. So in order words when you are using side-chaining on a sound the level of compression is being controlled by a totally different sound found elsewhere in your track.
Side-chaining is not just for drums anymore so experiment and see what else this effect might sound good on.
Not to be confused with multiband compression this is the technique of using several compressors on a signal instead of just one. The technique of using several compressors in the place of one compressor is not a new concept. The purpose is to take the load off just one compressor and to use compression in very small bits with several compressors all working together. This is kind of the same technique as serial compression but in my opinion it is much more subtle in it's approach.....well at least the way I like to use them. Now you will need to be carefully when you start applying 3, 4, 5, etc. compressors and it is too much to explain in this tutorial all the reasons you don't want to do that without a bit of caution. I promise I will explain this in more detail in a future article. The use of multiple compressors is an article in itself but it is important to take your time and understand what each compressor is doing to your sound.
These are just a few advanced methods of how you could use a compressor and is not meant to be an end all be all article on compression. It is meant to get you thinking about different compression techniques and how you can use them in your next mix so grab some plugins and try some things out. Remember if it sounds right then it is right. Happy mixing!
Article written by Alex Butler
Alex is an audio engineer, studio producer and freelance writer based out of Seattle, WA.