COMPRESSION

Compressors control maximum levels and maintain higher average loudness. Compressors and limiters are specialized amplifiers used to reduce dynamic range. The dynamic range is the distance between the loudest and softest part of a wave. A flute produces a tone where the difference is 3 dB. The human voice has a 10db dymanic range, while plucked instruments have about a 15dB range. Our ears act as compressors as well. Ears respond to the average loudness of a sound. Compressor are designed to include detecort circuits that responds to an average signal level. A second circuit responds to peak signal levels. A brick wall limiter hits a threshold and stops there, it wont be any louder than the threshold.
Multiband compression: Some compressors and digital plugins can separate the compression into 3 or 4 different bands of lo, lo mid, mids, and highs. This allows compression on only a certain amount or “band” of frequencies.
Compressors: Optical (LA2A, Fairchild 670) – use a photoresistor: signal comes in to a lightbulb. More audio = brighter light. Photocells can recognize the very suttle light changes caused by the incoming audio. FET (1176) – Field Effect Transistor: First transistor that emulated tubes in the way the work. They are fast, clean, and reliable. VCA – Voltage controlled amplifier – most versatile of all the compressors, have a higher level of control to control range. Varigain – doesn’t involve circuits, digital compressors – exaggerated compressors: all settings can be from 0- infinity, and you can get precision from this compressor versus the others.
Ratio – the degree to which the compressor is reducing dynamic range, of the difference between signal increase at the input and output. 2:1 means that for every 2 dB coming into the compressor, it will only sound like 1dB over going out.
Threshold – the level of the incoming signal at which the compressor amplifier changes from a unity gain amplifier into a compressor reducing gain. Everything above the threshold is being compressed . Once threshold is reached, compression happens depending on the amount of signal coming in, and the ratio setting. KNEE – hard and soft, the exact moment the signal reaches the threshold. A hard knee is sudden and abrupt. A soft knee eases on the compression. By manipulating the attack and knee, we change the envelope, mainly the attack and release.
Attack – brightness of character) the time it takes for the compressor to compress after the threshold has been reached. Attack times typically range from 1ms to over 100ms. The attack time effects tone in terms of brightness. Fast attack clamps down on the signal
Release – the time the compressor uses to return to unity gain after the singlahas fallen below the threshold. longer release time creates a darker sound, shorter relase makes it sound brighter. Compressor is released from gain reduction. 20ms – 5 seconds. Depends on the tempo and program material.
Fast release on a bass distorts it.
Slow attack – all the brightness comes through on a snare. Fast attack for snare – dulled sound
Brings loud portion down, and creates make up gain.
Send a snare track from protools out A 1-2 into line 1 inputs. Send that signal out of channel insert sends into the distressor, and then send the signal out of the distressor to channel insert returns. Start with the input, attack, release, and output to 5 on the distressor module.