What Is Compression in Music?
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Audio compression is the process of reducing your audio’s dynamic range. By reducing the dynamic range, you even out the loudest & quietest parts of an audio signal, giving a ‘glued’/’squashed’ sound.
Take a vocal track, for instance. Vocalists often have a huge dynamic range, & can go from extremely quiet parts to bellowing loud. To make the take sound more natural, and consistent, we can even out these changes using a compressor so they are more similar in volume.
From the two signals above, you’ll notice just how harsh audio compression can be if we over-use it. It can cause a mix to sound boxy or lifeless if we don’t use it correctly. So, that’s why we also need to understand how much to use (& when), to make sure our mixes sound incredible.
To give an analogy, compression is a bit like cooking: use too much spice and you’ve ruined your meal, but use enough and all the flavours combine together to make an incredibly tantalising, cohesive experience.
Know the insights of compression settings
There are 4 important aspects to keep in mind.
The compressor consists of 4 important parameters that needs to be adjusted to attain a perfect compression setting.
Threshold is how loud the signal has to get before the compressor begins to act on it. The value which you set this, is the level at where gain reduction will occur (where the compressor starts squashing the sound).
Ratio is how much compression is applied to the signal after it passes the threshold value in volume. The lower the number (1.5:1, 2:1, 3:1), the less compression that will be applied & the lower the gain reduction. The higher the number (5:1, 7:1 etc), the more compression will be applied.
Let’s say we have a 3:1 ratio. For every 3dbs your audio goes over the threshold value, it will only allow 1db to pass.
If that audio was to go 6dbs over the threshold, with the same ratio of 3:1, then only 2dbs would pass. With a 3:1 ratio, the volume is reduced by a factor of 3.
Attack and Release Controls
Attack is much like attack in the adsr synthesiser. It’s how quickly the compression is applied to the audio signal.
Release is, you’ve probably guessed it, how quickly the compression stops after the signal falls under the threshold in volume.