Compressors – What Are They?

A compressor is a really wonderful tool when engineering sound. What it comes down to, is its a tool that gives you more dynamic control over sound levels. For those of you who don’t know what a compressors is, I’ll give a quick explanation. A compressor does exactly what it sound like, it compresses the sound. How is compressed sound beneficial? Let’s consider the human voice. A talented vocalist is the most dynamic instrument on the planet. They can reach incredible high levels of dB and a second later be just a whisper. With such a wide range, it can be difficult to place the fader in a position that will accommodate both high and low dB levels. You would need to constantly be adjusting the fader so the vocals stay at the appropriate sound level.

A compressor can be set to compress sound at a certain threshold. This way you can use it to compress the higher dB levels, and increase the level out puts to bring up the levels of the quieter sounds. So the compressor changes the dynamic range of the track that the its applied to. Now we can her our vocalist’s quite whisper and at the same time not have his loud notes be clipping. Imagine that some one is turning down the fader every time the volume reaches that threshold point. Except this person on the fader is super fast and accurate.

Compressors are great tools when mixing and are also an essential tool for mastering. I’ll be giving more details in later posts on how and when to use a compressor. You don’t need to put a compressor on every single track, but only on those that you need to achieve a specific sound that a compressor generates, or a track that you need more control over the dynamic range then what you get with a simple fader.