Audio Compression Explained (In 3 Minutes!)

[00:00] In this video, I'm going to quickly explain how compression works. Compression was originally thought up as a way to deal with uneven volume on vocals.

[00:16] Some words would typically be too quiet and some would be too loud. Compression was the ideal way to fix that problem. When compressed, the words would have a more even volume overall.

[00:30] Today, we use compression on just about everything, like drums, bass, leads, and so on. Compression can be used to control the apparent fullness of a sound. It can be used to control the transients as well as the body of a sound, to make it crisper or fatter.

[00:49] Let's take a look at this waveform. This is how a typical waveform from the early days of music would have looked like. You can clearly see the difference between loud and quiet elements in the track.

[01:01] This relation between low and high volume is what we commonly call dynamics or dynamic range. Dynamic range is very important in music because of the way our hearing works. The thing is, in order for something to be perceived as loud, something else has to be quiet.

[01:18] You might say that our hearing needs a frame of reference. It's like looking at several mountain tops on the horizon and they're almost equally tall. It's then very difficult to say which one is the tallest.

[01:30] When a track becomes overly compressed, the waveform tends to look like this. You probably recognize it, right? This track has been squashed like most tracks these days thanks to the loudness war.

[01:44] It's been heavily compressed and limited. In order to understand how this works, we need to understand how a compressor works. A compressor is actually very simple. It does exactly what its name suggests.

[01:58] It compresses the signal. When a compressor does this, it reduces the volume of the loudest elements. A makeup gain is then added to bring the overall volume back up. Depending on the amount of compression, the dynamic range is decreased accordingly.

[02:14] The difference between loud and quiet becomes less and less. Compressors can be quite useful when used on vocals, for example. A singer will typically sing with a great variable of intensity throughout the track.

[02:28] A compressor can then help make the overall intensity more even. If some words are too quiet and others too loud, the quiet ones will be increased and the louder ones will be reduced, resulting in a balanced mix.

[02:42] But as any tool, compression can also be abused and overused, which is what the loudness war is all about. I actually have done a video about this, so if you haven't seen it yet,

[02:54] I strongly recommend that you check it out. There will be a separate video explaining how to actually use a compressor later on, as part of my How to Mix series. I'd like to thank our patrons for their ongoing support,

[03:06] and as always, if there's any specific tutorial you'd like us to make, or if you have a question, just let us know in the comments below. Thanks for watching!