Compression Part 1
Compression is just about one of the most complicated things you’ll come across with audio. Many questions arise when using compression such as…
•What does it do?
•Why use it?
•How much is too much?
•As well as many other questions and issues that arise.
We’ll look at compression in a few parts as it can be quite overwhelming and can take years to fully understand what it is doing and how to use it properly.
Let’s first look at what compression essentially does overall. Compression is mainly used for dynamic control. It essentially reduces the loud sounds and increases the quieter ones, as seen in the below picture.
By doing this, it not only increases the overall volume of the sound (once you use makeup gain), but it also completely changes the tone of the sound you have compressed. This is why something might sound a lot “fuller” when it has been compressed, as it will bring up the softer frequencies and in the case of a voice over, the softer frequencies tend to be the lower frequencies, so compression will add a lot more grunt to the voice.
Why not just add lots of compression then? Well if you start to add too much compression you’ll start to hear the effects of “pumping” caused by over compression. This is where the audio has audible unnatural changes in level. Another thing that can happen once we pass this stage is distortion. Finally once production has taken place, extra compression will probably be added to your track that is out of your control. This may occur at a mastering house, a radio or television station or somewhere else before your audio reaches its end destination.
So now we know what the basics of compression are. In the next blog we’ll cover the benefits of compression and how to use it properly. Stay tuned for another exciting episode of compression (well exciting if you’re an audio nerd).