Compression is a vital tool in audio production, capable of subtle enhancement or dramatic transformation of your sound. This guide will take you through the basics of compression and how to apply it effectively in your mixes.
What is Compression?
Compression is a process that reduces the dynamic range of an audio signal. In other words, it makes loud sounds quieter and quiet sounds louder, bringing the overall volume levels closer together.
Key Compression Parameters
- Threshold: The level at which the compressor starts to work.
- Ratio: How much compression is applied once the signal exceeds the threshold.
- Attack: How quickly the compressor responds to signals above the threshold.
- Release: How quickly the compressor stops working when the signal falls below the threshold.
- Knee: How the compressor transitions around the threshold point.
Remember, compression is an art form. While these parameters provide the technical framework, your ears are your most important tool. Always listen critically to the effect of your compression settings.
Compression Techniques
- Subtle Dynamics Control: Use a low ratio (2:1 or 3:1) with a higher threshold for gentle leveling.
- Punchy Percussion: Fast attack and release times can add punch to drums and percussion.
- Glue Compression: Apply light compression to a group of instruments to make them sit together better in the mix.
- Parallel Compression: Blend compressed and uncompressed signals for a powerful yet natural sound.
- Sidechain Compression: Use one signal to trigger compression on another, great for creating space in a mix or for effect.
From Subtle to Squashed
- Subtle: Low ratio (2:1), high threshold, slow attack, medium release.
- Moderate: Medium ratio (4:1), medium threshold, medium attack and release.
- Heavy: High ratio (8:1 or higher), low threshold, fast attack, slow release.
- Squashed: Very high ratio (20:1 or higher), very low threshold, fast attack, fast release.
Creative Uses of Compression
- Sustain Enhancement: Use a slow attack to allow transients through, then compress the body of the sound.
- Pumping Effects: Intentionally over-compress for a rhythmic pumping effect, popular in EDM.
- Tone Shaping: Some compressors impart a pleasing coloration to the sound when driven hard.
Remember, while heavy compression can be a powerful effect, it’s often the subtle application of compression that separates amateur from professional mixes. Always consider the context of your mix and the genre you’re working in when deciding how to apply compression.