Compressor Flashcards
Compression
Developed in the 1920s and 30s
Was used in radio to control output levels
If not used, levels were at risk of damaging other equipment
The same principle applies today, we use to control level
What does a compressor do?
Reduces the dynamic range of a sound by controlling the volume of the loudest parts while boosting quieter sections
Won’t be noticeable when used correctly
Basics of a compressor (Not in spec)
A compressor splits the incoming audio signal
One to an amplifier, the signal we hear
One to a side chain to measure the signal
The measured signal is used to control the level of the audio, the louder it gets, the greater the compression
This is the feed forward method
Early dynamic limiting (1930s)
The earliest limiting amps were not designed for studios
As well as broadcast they were used on PA systems
A compressor on a PA system creates an even dynamic
This avoids peaks (Peaks blow speakers)
RCA 96-A was the first device to be called a compressor
The optical compressor (1958)
Invented by Teletronix with the LA-1 model
The signal is converted to light, the brighter the light is, the louder the signal is
Then the Light Dependent Resistor detects the light
Depending on the brightness of the light, the compressor controls the sound (The brighter it is, the more compression will be applied)
A smooth, natural compression with a slower attack
The replacement mode the LA-2A is still popular today
The FET Compressor (1967)
The first solid-state compressor
Much more consistent operation compared valves
A very ‘transparent’ compression
Can combine all 4 ratios
Creates a very aggressive limiting when used
Multiband compression (c.? 1970s)
Nobody knows when multiband compression was invented
Early experiments had been around for some time
The Dorrough Model 310 DAP was launched in 1973
3 bands of compression for different frequencies
So different levels of compression can be applied at the same time
Smooth crossover between bands
The VCA Compressor
Uses solid-state technology
But compression responds like a valve circuit
More refined control over attack, release, ratio and knee so more control over the sound
The Dix 16 was the first VCA compressor
Other compressors (1970s-1990s)
Consoles started to include compression on each channel
Famous consoles had distinctive compression sounds
The SSL Bus Compressor
Never 33609
Evolutions of existing technology improved compression response and clarity of sound
Side chaining
Uses a separate signal to control the compression level
Generates compression when other audio plays
Often used to bring a kick drum out in a mix
Current compressors (2000 onwards)
Most compression now in box
Early DAWs featured basic compression
Now include range of compression styles
More interest in vintage compression sounds
Models are re-issued and cloned
