Compression Part 1

This post is going to teach you about compressors and limiters. Compression

is one of the essential recording and mixing tools. It's commonly misunderstood,

misused, and overused.

First, let's look at what a compressor does. A compressor simply makes louder

things quieter and quieter stuff louder. Thus, evening out the audio. Then,

you can boost that squeezed, compressed signal up to a louder, smoother, and

more even audio signal. Limiters are basically compressors that use a higher

compression ratio.

Now, let's look at the knobs and controls on typical compressors. The main

control, and probably the first knob you'll turn, is the threshold control.

This will allow you to control when the signal passing through the compressor

will be compressed. So, if the threshold is set to, let's say, -5dB. The

audio that is quieter than -5dB will be unaltered. While the audio that is

over -5dB is compressed, or brought down in level. The next control knob

is the compression ratio control. These are labeled as 2:1, 4:1, 10:1, etc.

The compression ratio simply tells the compressor how much to reduce the audio

signal that is over the threshold control. Let's look at the 4:1 ratio. This

means that for every 4dB over the threshold, the signal is only going to be 1dB

louder, not the full 4dB. There's your compression of audio. Next thing to

look at is the gain knob, which is sometimes labeled as the output. This control

brings your level up to make up for the ratio of compression that squeezes down

the overall volume.

Now, you can go use any compressor you come across in your recording and mixing.

There are some other features that include attack, release, soft/hard knee

control, and input control; however, knowing the most common knobs that I have

went through with you will give you the production skills needed to use

compression to your advantage. In part two on compression, I'll go into

the other features of compressors.