Saturday, December 22, 2012

Audio Compressor least understood misused audio processors

Audio Compressor is one of the least understood and most misused audio processors.
Many people don’t have any idea how to use compression in their recording projects.  I have a friend with a home recording studio that said “ I don’t know what it does but I put it on my tracks, what does it really do?”
Well its something that is hard to explain in a few words but I will give it a try.
Compressors are specialized amplifiers used to reduce dynamic range--the span between the softest and loudest sounds.
There are four basic parameters on all compressors: compression ratio, threshold level, attack time and release time
Ratio: A way to express the degree to which the compressor is reducing dynamic range. Ratio indicates the difference between the signal increase coming into the compressor and the increase at the output level. A ratio of 10:1 would mean that it would take an increase of 10 dB coming into the compressor to cause the output to only increase 1 dB.
Threshold: Threshold is the level of the incoming signal at which the compressor amplifier changes
The compressor has no effect on the signal below the threshold level setting. Once threshold is reached, the compressor starts reducing gain according to the amount the signal exceeds threshold and according to the ratio control setting. Threshold level could be thought of as the "sensitivity" of the compressor.
Attack Time: Attack time refers to the time it takes the compressor to start compressing after threshold has been reached. Example: set a slow attack time on a snare drum so you get the hit of the snare dynamic .  If you have a fast attack time on a snare hit you will notice a diminished or shortened attack of the hit.
Release: Release time is the time the compressor uses to return to unity gain after the input signal has fallen below threshold.
This is a quick explanation to get you started.

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