Last time we looked at the basics of what a compressor is, and what it does. In today’s post, we look at common uses of compression in music production, so you know what you’re trying to achieve when you fire up your compressor – essential for using it well.
We won’t get into specific settings as that always depends on the material you’re compressing, rather, this is about reasons why you might use compression.
The most basic use is to even out inconsistent levels by bringing down the loud bits. It’s often said that ‘the most transparent compressor is you’ which is true – if consistent levels are what you’re after, you might be better off with volume fader automation.
However, if you’re pushed for time, lazy, or after something more than just consistent levels (see below) then compression is the answer for you.
Thickness is one of those near-mythical qualities often ascribed to compressors. Essentially, it’s a by-product of reducing the dynamic range, but the amount of thickness you get is dependent on what type, and model, of compressor you’re using.
Thickness is one of those things that people often say is far easier to achieve with analogue, and tubes in particular are renowned for sounding ‘fat’ (the Manley we use for mastering certainly does), but there are some very natural sounding plug-ins that do a great job.
Fabfilter’s Pro-C is a versatile and affordable compressor, and Stillwell Audio’s Bombardier is reputedly great for mix bus duties.
The level of ‘punch’ you get is again incredibly dependent on how the exact compressor you’re using reacts, but by and large any compressor can achieve it.
Punch is achieved by allowing transients (the ‘attack’ portion of the signal) through before compressing the remainder. It’s a consequence of the difference in level between the attack and the sustain.
It depends on the material, but greater punch (and more natural sounding compression) is usually achieved with slower attack settings, and medium release times.
Completely dependent on the compressor you’re using. Some compressors become famous for their tone, while others are known for their transparency. It’s really a matter of taste when it comes to character.
Our Manley gives a great tube vibe to anything put through it, but the TC Electronic MD3 is so transparent you almost wouldn’t know it was there (except that everything sounds better). Each has their uses.
Another near-mythical quality of compression is ‘glue’. Generally referred to for sub-mixes or across the whole mix, compression can make everything sit together in a cohesive way that is difficult to achieve without it.
Again, some compressors are better at it than others, and you probably won’t get that close to ‘glue’ with a generic stock compressor or workman-like plug-in. This is what high-end outboard (and emulations thereof) is essential for.
It’s been said that loudness is the mastering engineer’s job, and compressors are his weapons. This is a simplification of course, but it’s also very true.
Achieving loudness across a whole track is an art, but in simple terms is a case of raising the level of the whole track without harming the peaks. If you compress too much you lose transients, and therefore the attacks of notes, and the music loses all impact. Compress too little and you have a quiet track.
(Naturally there is more to achieving loudness than just compression, but it does go a long way…)
The same principles can be used for amplifying individual parts – something live engineers struggling to get the vocal above a loud drummer will be familiar with.
Whatever you’re using compression for – make sure you know why you’re using it and you’ll get far better results.
Next time: different types of compressor and their uses.