compression is an audio signal processing operation that reduces the volume of loud sounds that are irritating or amplifies the quiet sounds that are barely audible; therefore it reduces or in other words compresses an audio signal’s dynamic range.
Dynamic range is the difference between the loudest and quietest parts of an audio signal.
You need to reduce the dynamic range of most audio signals for them to sound natural on a recording and ultimately be comfortable to listen to. Compression is one of the most powerful tools in the mixing business, and it’s an essential element behind every good mix.
You have to be careful because compression is just a tool, how you use that tool is of significant importance because every compressor regardless of it being hardware or a plugin has its own unique signature sound that can be used to inject wonderful colouration and tone into your tracks.
A compressor can drastically change the tone and quality of a sound however if used poorly; it can also ruin your entire work; therefore, it’s crucial for you to understand how compression works, what are its different parameters and how you should adjust them based on your desired outcome.
Compressors have a verity of parameters, and whether you are using a hardware or a plugin compressor, there are a number of adjustable control parameters and features that are used to dictate the behaviour of the compression effect and adjust dynamic range compression signal processing algorithms and components.
Some of these controls are as follows:
Input Gain controls the level of the signal going into the audio compressor.
The threshold control sets the level at which the compression becomes activated. The compressor reduces the level of the audio signal if its amplitude exceeds a certain level. Only when a level passes above the threshold will be compressed. For example, If the threshold level is at -10 dB, only signal peaks that extend above that -10db will be compressed. And the compression will not affect the rest.
ratio specifies the amount of attenuation that should be applied to the audio signal. Or to put it simply Ratio determines the amount of gain reduction your compressor should apply when the audio signal goes above the threshold that you selected. The higher the Ratio, the more compression there is.
For example, a ratio of 4:1 means that if the input level is 4 dB over the threshold, the output signal level is reduced to 1 dB over the threshold. The gain and output level has been reduced by 3 dB.
Attack is one of the features that if used properly, can drastically change the tone of a sound. Using the Attack control, you can set the time that the compressor takes to act on the input signal once the sound level has gone over the threshold level. The Attack is the timing with which the compressor’s gain reduction starts (It’s usually measured in milliseconds (ms)).
when the signal goes above your threshold, the compressor will begin to reduce the gain based on the ratio you set; Release is the time that the compressor takes to let the signal return to normal once it has fallen below the threshold level. And its also usually measured in ms.
When the audio signal is compressed, the overall level of the signal is reduced therefore Increasing the output gain raises the level coming out of the compressor, so the volume can be more easily matched to the levels of the rest of the tracks in the mix.
Hardware or plugins?
Hardware compressors are huge and they usually take so much space not to mention that good one’s are always super expensive and super hard and expensive to maintain they require constant service and attention
although hardware provides a more natural and saturated sound, but these days with the development of technology and plugins being modelled after real hardware, plugins give you almost exactly the same tone with more flexibility, these days plugins can mimic almost 70% of hardware sounds so if you cannot afford hardware don’t worry you can make great sounding records just behind your computer.