Why The Pros Use Compression (And How Simple It Can Be)

Take a journey with me back almost 20 years ago when I was starting to record and mix my band in high school and let’s listen in to the mind of High School Graham circa 1999:

“Wow, this whole recording and mixing thing is harder than I thought it would be. What am I missing?!” – High School Graham

Graham would scour the internet (on a slow dial up 56k modem) looking for articles (no YouTube yet!) on what he was missing when it came to making his mixes sound professional.

“Certainly there has to be some trick or specific plugin I’m missing that all the pros use!” – High School Graham

Eventually he stumbled upon what seemed to be the difference maker…compression!

How Hard Can Compression Be?

There was a clear pattern in all of his research and Graham couldn’t be more happy to have discovered it.

“Eureka! I found it! The thing that my recordings and mixes are missing is this mysterious effect called compression! Every interview I read from all the big boy mix engineers involves some conversation about compression or their favorite compressor. All I need to do is use compression when mixing!” – High School Graham

So, poor little newbie recording engineer High School Graham started to insert compressor plugins into his pathetic mixes and discovered a heart breaking truth:

Just knowing you need compression isn’t enough. Truly understanding what it does and how to implement it in your mixes is the key!

Which brings me to today.

The Graham of today uses compression on every mix. So do all of the pro mixing engineers you and I admire.

But none of those guys (and gals) use it blindly. They have a plan for it. A reason for every instantiation of every compressor plugin.

The good news is, compression is a lot simpler than I used to think.

And today i’m going to walk you through 4 things you need to know about compression so you can start getting punchy, exciting, and well balanced radio-ready mixes in your home studio.

This Is All Your Compressor Does

Before we dive in, let’s just be clear about what a compressor does in the first place.

At it’s most basic (and I love basic) a compressor is simply an automatic volume fader control device. It can literally turn down loud stuff automatically and give you a more even volume throughout. That’s it!

Why is that helpful?

Well most music is very dynamic, meaning it gets loud and soft with great variety throughout a song. This can make it hard for an instrument or vocal to be consistently heard and felt throughout in a final mix. Compression, can help you get that nice, consistent, up front sound you’re after.

To be fair, compressors are used for more than just volume control. They can give something more energy or more sustain. They also can act as tone shaping devices.

But for today, let’s look at the knobs and tweakable settings on a typical digital compressor plugin so you can feel right at home and in charge!

Threshold

The most important knob on a compressor in my opinion is the threshold. It’s the knob that actually allows compression to take place or not (and how much).

It makes absolutely no difference whatsoever how much you’ve tweaked the other settings on the compressor, if the threshold is set at 0db (or the top) then no compression is actually happening.

Threshold is the volume at which compression kicks in. It’s like a “master control” on the whole darn plugin.

Turn it down a tiny bit, and the compressor will only affect the loudest peaks of the track. Turn it down a lot more, and you’ll get even more squash to your signal.

A great rule of thumb for natural sounding compression is to turn it down and watch your “gain reduction” meter until you’re seeing around -3db to -4db of gain reduction.

Ratio

Another knob that works in tandem with threshold is the ratio. The ratio knob controls how hard the compressor hits when signal crosses the threshold.

A 1:1 ratio means the signal isn’t turned down at all. It’s a flatline. A 2:1 ratio tells the compressor to turn down any signal that crosses the threshold in half. (For example if signal crosses the threshold by 6db of volume, a 2:1 ratio would turn that signal down to only 3db above the threshold.)

The higher the ratio, the more squashing you get. Basically you can play with the ratio and threshold knobs together to get as much or as little compression as you like.

Attack And Release

If threshold and ratio control how MUCH compression (or volume being turned down) is happening, then the attack and release knobs control how fast the compression kicks on and off, thereby affecting the tone.

The faster the attack setting, the quicker the compressor pounces on your audio when it crosses your set threshold. And the faster the release, the quicker the compressor resets or “lets go” of the signal.

Attack and release are game changers because they basically change how your compressor sounds and what it does to the audio.

The best suggestion I can make is to keep attack and release in the middle as a starting point, and then experiment with much faster (and slower) settings, noting what affect they have on your track in question.

You’ll soon discover what sounds cool on what type of audio (and what doesn’t).

Makeup Gain

The last compressor setting I want to address today is makeup gain (or sometimes simply “gain”).

With all this turning down of the signal (because remember, that’s all a compressor is meant to do), you’ll have a much quieter track than when you started. The solution? Simply turn it back up a bit.

Thankfully for us, engineers were smart and put a simply output gain stage at the end of compressors to “makeup” any lost volume or gain.

If your compressor is on average turning down your snare drum (let’s say) by 4db with every hit, then it’s safe to say you can turn the makeup gain knob up around 3db to 4db. The goal is to level match it to the original signal going into the compressor.

The difference, though, is that now you have a much more consistent signal coming out of the compressor, than you had going in. – Which is the whole point of compression.

The Simple Guide To Compression

While many compressors have other settings like knee, key input, etc, ignore them for now. All that matters for 90% of the time are the four main settings I’ve shown you here.

Want to go deeper?

Interested in learning things like stacking compressors or parallel compression?

Or maybe you just want to avoid the 3 biggest compression mistakes I see home studio owners making every day!

Lucky for you I’ve put all of that together, plus the concepts I’ve been teaching today, all in one easy to access and absolutely free guide.

Check it out now, apply it to your mixes, and you’ll notice the results!