From Home production

Beginner’s Guide to Compression: Part 2 – Common Uses

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.

Consistent levels

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

Stillwell BombardierThickness 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.

Punch

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.

Colour/character

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.

Manley Vari-Mu

Glue

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.

Loudness

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.

A Beginner’s Guide to Compression: Part 1 – The Basics

Compression is possibly the most misunderstood tool in the music production toolbox, but also one of the most useful. Really understanding how compression works is essential to using it effectively, and good use of it is at the heart of the way probably all of your favourite records sound.

Here then, is our back to basics guide for those that could do with a little more knowledge, and those that could do with a reminder.

What is it?

The most basic function of a compressor is to act as an automatic gain rider. You might hear it said that ‘the most transparent compressor is you’.

That’s because at its most practical, a compressor is simply an automated way of carrying out fader rides to even out a level. If you ever do any work in broadcast or film, this is the common use of a compression – using it to make sure nothing goes over a pre-specified level.

The consequence of pushing the loud bits down is that the dynamic range is reduced. If you then amplify the compressed signal, this will have the effect of bringing up low level detail as well as reducing peaks. Ironically, by pushing high levels down you can make something louder and/or achieve that mythical ‘thickness’. This is the one of the more common uses in music production – particularly in mastering.

How does it work?

To understand how a compressor works, let’s take a look at the controls you’ll find on nearly every compressor:

Threshold
Threshold is where you set the level at which the compressor will act. So if you set a threshold of -20dB, any signal that reaches that level will be affected by the compressor. Anything below that will remain untouched.

This is why it’s important to always tweak the threshold on compression presets – the threshold is entirely dependent on the signal you feed into it. If you’ve recorded something quiet and the preset has a threshold of -5dB, it’s not going to do anything.

Ratio
Ratio specifies how much the gain is reduced by once it hits the threshold. So, if you’ve got your threshold at -20dB with a ratio of 2:1 and you have a -18dB signal, (2dB over the threshold) the compressor will reduce the level by 1dB (to -19dB). If the signal is 4dB over the threshold, a ratio of 2:1 will reduce it by 2dB.

Attack
Attack specifies how quickly the compressor will act once the signal goes over the threshold. Leaving a longer attack time will let more transients (the initial ‘attack’ portion of the signal) through resulting in a more natural sound, a shorter one will allow less and result in a more ‘squashed’ sound.

Release
The release control sets how long it will take for the signal to return back to its original level after the compressor has acted. How you set this really depends on what you’re trying to achieve. If you’re trying to even out a level, longer times (200-300ms) are best, but if you’re just trying to address peaks, shorter release times are more appropriate.

Makeup gain/output
This control sets how loud the final compressed signal is outputted. It is often called Makeup Gain as a reference to how you are making the finished signal louder to compensate for reducing the loud portions of the signal.

Understanding how these controls work will go a long way to effective use of compression. The trick is to know what you’re trying to achieve first, and knowing how to achieve it second.

Next time we’ll look at common uses of compression in music production. If you have any questions, post them in the comments!

What Makes a Pro a Pro

One thing almost every home studio owner has in common is a lack of confidence. Not having been to studio school or worked their way up in a professional studio has led them to question their ability. But it’s not a degree or years of making the tea that make a pro a pro, that’s just how a lot of people get there.

There’s no reason you can’t get be a professional without a laminated piece of paper or an aversion to tannins.

Knowing when it’s right

The major difference between professionals and amateurs (and this is true in any industry, not just recording) is knowing when it’s right.

This means two things:

  1. Knowing when to hold back
  2. Not accepting substandard results

The first is a case of knowing when something’s right and leaving it well alone. One of the most common amateur mistakes is over-processing, whether through not recognising a finished product or trying to justify themselves. Sometimes (very occasionally) your role as a live/mixing/mastering engineer is just to say that it’s right. Not everything needs your killer reverb preset.

The second is never calling a project finished until it is. If you’re under time constraints it’s fine to go for the best you can achieve in the time. But otherwise, if you know something’s wrong, don’t accept it and move on. Figure out how to fix it. If you don’t already know, experiment, Google it, ask someone else.

Knowledge

Of course, you won’t always know how to fix something, or what something should sound like. And that’s where experience comes in. You won’t always get it right, but another mark of a consummate professional is admitting when you don’t know something and ceding to someone who does.

Don’t be afraid to say ‘I don’t know.’ If you’ve tried everything you can and it’s still not right, don’t just say it can’t be done. Give it to someone who can do it and find out how they do it. Then next time you’ll be able to do it yourself.

There’s very little that can’t be done with modern recording technology – even with stock plugins. If you really can’t get something to sound right, chances are there’s some little trick out there that you don’t know (yet).

Tools

Notice how tools is the last section? That’s because although most of us in this industry geekily obsess over gear, it’s not the gear that makes the pro. It’s how you use it.

If you’ve got a reasonably up to date DAW, a decent set of speakers in a decent sounding room, you’ve already got the tools. Everything else is adjusting to taste.

This post is the last in a loose trilogy of posts about achieving pro results from home recording equipment – read the first two: The Biggest Mistake Home Producers Make and Making it Sound Deliberate.

Photo credit spjwebster