Compression is one of the most important plugins to master. It helps you adjust the correct amount of depth in your tracks, soften peaks, and levels the dynamics of your audio.
First, there are a couple types of compression you should know about:
Basic Compression - General compression limits the dynamic range in a track. The dynamic range is the distance between the loudest (highest dynamic) peak in the track and the quietest (lowest dynamic) peak in the track.
Multiband - Same as basic compression, but the option to affect specific frequencies of the track similar to EQ.
Parallel - Keeps more of the original sound of the track by running the original audio alongside compressed audio. Most compressors have the option to run in to parallel by using the mix setting.
Serial - Multiple compressors in line on same track. Also helps keep the natural, original sound because you compress in stages as opposed to one single compressor doing all the work.
Next, here are most of the options or settings your compressor may have:
Ratio - The ratio at which the audio is compressed.
Attack - How quickly the compression is triggered when audio reaches threshold.
Release - How quickly the compression stops when audio drops below threshold.
Sensitivity/Threshold/Compress - Sets the level to engage compression.
Makeup - Adding compression naturally quiets the track. Makeup helps get back the lost loudness. A good starting point is to add as much makeup as gain reduction took away. Not always easy to see on all compressor plugins but having a general idea is still a good place to start.
Mix or Dry/Wet - Usually in %, let’s you know the percentage of dry (uncompressed audio) and wet (compressed audio) coming out of the plugin. This is where you can turn a standard compressor to a parallel compressor.
Knee - How gradual the ratio is applied to the compression. A higher dB knee makes a softer knee, lower dB gives harder knee. If you have this option a softer knee is typically best.
Difference between Peak and RMS:
Root Mean Square - average of the sound signal
Peak - loudest signal
In general, if you’re looking to get rid of harsh S’s or some extreme peaks obviously that’s where a peak based compression could suit best. If you don’t have sharp dynamic changes in the song, changing to RMS could be beneficial.
-If needed, heavier compression is typically best suited early on individual tracks.
-For a more natural sound, use parallel compressors with the serial method. But be cautious as multiple compressors can do far more harm than good if used too aggressively.
-Very mild compression on the master to glue it all together and make the entire track cohesive dynamically.
-Less is more!