COMPRESSION

Dynamic Range Processing

Compressors are dynamics processors.  They change the dynamic range of a sound– the distance between the quietest and loudest part of the sound– by reducing peaks so quieter parts of the sound can raised.

Dynamic Range Review

• The dynamic range of a sound is the difference between its quietest and loudest parts.
• The dynamic range of a system is the difference between the noise floor and distortion.

Words of Warning:
This stuff is hard!

• The way we perceive amplitude is complex and changes quickly.
• Compression can be hard to hear easily.
• Compressors have less consistent controls than EQs (especially vintage models, so don't start there).
• Parameters may not seem intuitive.

Examples

Basic Controls

1. Threshold:  How loud is a sound before compression begins?
2. Ratio (Input:Output):  How much does the compressor turn down sound above the threshold?

Compressor Graph

Basic Controls

1. Threshold:  How loud is a sound before compression begins?
2. Ratio:  How much does the compressor turn down sound above the threshold? 
3. Make-up or Output Gain:  Once the peaks are turned down, how much does everything get turned up?
4. Gain Reduction Meter:  How much is the compressor working at a given moment?