Dynamic Processing

Compression

Reduces dynamic range of a sound/signal

Limiter

Limits the volume output, useful on the master track to avoid clipping

How Compressions allows increased volume

Reduces the dynamic range allowing you to increase the make-up gain to increase volume without peaking

Make up gain

Gain applied after signal has been compressed

Manual compression

riding the fader by adjusting the volume when an instrument gets to loud while recording

Threshold

determines at what amplitude the effect kicks in

Ratio

By however much the amplitude peaks the ratio is applied in how much it is compressed

e.g. A signal exceeding the threshold by 8 dB will be attenuated down by 4 dB if the ratio is 2:1

Noise Gate (Gate)

Cuts out sound below the threshold

Parameters of Compressor

Threshold: volume that the compressor activates

Knee: How ‘hard or soft’ the compressor activates

Ratio: Amount of gain reduction

Attack: How fast the compressor starts compressing after threshold is reached

Release: how fast the compressor stops compressing when below the threshold

Parameters of a noise gate

same parameters as compression except for ratio:

Reduction/range: amount of volume the signal is reduced by

Hold: amount of time gate stays open after signal drops below threshold

Compression post 2007

Control over compression increased allowing more subtle compression

Origins of compression

In the 1930s and 40s when radio networks needed a way to control the audio signal, to prevent a distorted transmitted signal

Sidechain compression

Compressor triggered by the volume of one track but the compression is applied to another

Multi-band Compression

allows you to change the frequency bands, ensuring you can change the compression levels of certain frequency bands rather than the full bandwidth.

Multi-band compression is good for mastering.

First commercially available compressor

1937 – The Western Electric 110A limiting amplifier

Loudness wars

‘Louder is better’ trend in 1990-2000s where masters and remasters produced very loud and with low dynamic range

X and Y axis on compression graph

X: input level (dB) Y: Output level (dB)

the affect a fast release causes

pumping or ducking

One More Time - Daft Punk (2001)

uses sidechain compression on kick to create pumping sound

De-essing

sibilant sounds controls frequencies between 5-10KHz

Expanders

reduce level of signals that fall below a set threshold expanding the dynamic range

why loud masters are important

playback on small equipment

masks noise on analogue recordings