A lot of people have difficulty in using an audio compressor in the correct manner. A audio compressor is essential for every audio engineer or producer's success. A compressor is needed in every studio no matter how big or how small, especially if you are planning on recording a lot of vocal lines.

Before we look at using an audio compressor we should first look at what a compressor actually does to a signal. Simply put, a compressor basically squashes ( compresses ) a signal so that if fits better into the overall song. Personally, I cannot do without a compressor in my productions. I'm not saying they are easy to use or get used to because they are not - they take a lot of trial and error before getting to grips with.

So what are the parameters involved with using an audio compressor? Lets start with the 'threshold' of the device. The threshold sets how high the signal must reach before the compressor starts working - anything above this threshold level will be compressed. The 'input' of the compressor is fairly self-explaining rely, it just set's the level of the signal going in ( you do not want to overload the input signal of any audio device ).

The ratio is where using an audio compressor gets a little confusing. The ratio is the amount of signal you want compressed above the threshold. It's the ratio of the signal in db you want reduced or compressed. The 'attack' and 'release' of the compressor work together really. The attack is how fast the compressor starts working and the release is how long the compressor holds the signal for. For example for high velocity instruments you will probably use a short attack. For guitars I normally set the attack at about 16ms because they have a very fast velocity once a string is hit. The release I will set at about 190ms because I do not want the compressor to hold the guitars sound for to long.

Attack and release will vary on what you are recording. As I pointed out the guitar is a fast moving instrument so the settings reflect that. If I am recording vocals I will set the parameters a little longer, for attack I set it around 25ms and the release at 300ms. As I said earlier in the article using an audio compressor is all about trial and error. I doubt you will be able to set the the parameters the same every time as the recorded signal will be constantly changing. Good luck with your production!