How To Use Compressors
October 09, 2019Compressors are some of the most powerful tools available to recording engineers and mixers in the studio, but they also happen to be misused the most often. Whether from a misunderstanding of the fundamentals of compression or willful ignorance, mixers will often use the wrong settings on their compressor for the audio source they’re working with.
If you’re someone who’s relying too heavily on presets to get you where you need to be or you’re wasting hours twisting and turning knobs and sweeping through settings you don’t understand, I want to dispel some of the misconceptions about compression and teach you to use them more effectively in your mixes. Let’s start with a basic concept: what exactly should a compressor do?
The Purpose of Compressors
The entire point of using compression in your mixes is to maintain better control over the dynamics of your session. Audio sources that have inconsistent levels, loud peaks & quieter parts that struggle to cut through are all prime candidates for compression. For some sources, you’ll just want to pull down those peaks . In other situations, you’ll want to apply more compression so that you can bring up the overall level of that track. While your reasons might differ from instrument to instrument and session to session, the core concept of compression remains the same – you want to maintain better control.
Start With Your Threshold
Assuming you’ve got a decent signal level feeding into your compressor (no clipping), your first step should almost always be with the threshold. Set your threshold to a level where you want compression to start pulling down the peaks of your signal. A higher threshold might make sense if you’re just trying to cap how high your peaks go, but a lower threshold is going to start compressing your signal sooner and more frequently throughout the session.
I tend to look for the sweet spot somewhere above the average level of the track that catches a lot of the peaks but doesn’t keep the compressor engaged 100% of the time. Look for your loudest parts and use that for reference as you work. At this stage, we don’t care about how much compression is being applied or the style of compression being used – we just want to find that crossover point where we know compression is needed.
Compression Ratios
The ratios on your compressor are what determine the amount of compression being applied to your signal. Use a lower ratio when you want some level of gain reduction on your peaks while still allowing them to extend beyond your threshold. Higher ratios will start to act more and more like a limiter as you work your way up; the highest compression ratios won’t let anything get past your threshold.
As you might have guessed, higher ratios also tend to be the most noticeable to listeners, so aggressive compression should be used for effect or when you’re truly trying to get a heavily compressed tone on a track. To lessen the reliance on one compressor to get the job done, professional engineers and mixers will often compress in stages – loading a couple of compressors in serial to compress a little at a time.
For more on compression ratios, be sure to check out our guide on How Compression Works .
Coloring With Compressors
Have you ever seen or heard of somebody using a compressor with a 1:1 ratio or a threshold so high that they’re not really catching any of the peaks? Maybe they’re misusing their compressor, but if they’ve been using compression long enough, there’s a good chance their simply adding some character to their source .
Gain Reduction 2 is the perfect example of how a compressor can be so much more than a compressor – working to add some color to your track in the process. With controls like Breath, Warmth & Air – the plugin works to shape your tone as part of the compressor circuit, adding character in the process.
This isn’t a new technique either.
Pros have been using the SSL Bus Compressor on massive recording consoles for their color for as long as they’ve been around. The enabling of the compressor simply adds glue to any mix , even if the needle isn’t moving and the threshold is set to its max level. Another common studio compressor that makes use of the 1:1 ratio is the Distressor, which also adds some bells & whistles giving it a distinct sound.
With so many great options, compression is a great way to add to your sessions harmonically while controlling your dynamics at the same time.
Where Does Compression Fit In Your Mix?
Compression alone is a tough concept to fully understand, but it can get even more difficult if you’re not using it correctly in your signal chain. Knowing when to use it before an EQ and when to use it after can make a huge difference in how effectively it works on the incoming signal. Finding the right settings on an Aux or Master bus can literally make or break your session.