The term parallel compression is almost always heard when top engineers are talking about their recording or mixing techniques. It’s a technique used by almost everyone and made famous by, for example, Andrew Scheps, Vance Powell and many others. It’s a great technique that allows you to shape the envelope or manipulate the feel of an instrument/s with just the use of a compressor.
But what is parallel compression anyway?
Simply put, it’s sending a bunch of your tracks, for example, drums, bass, guitar, you name it, to a bus and on the return having a compressor set up. The compressor can be set up in a bunch of various ways, depending on what you desire (more on that later), for example, to make something pump, breathe, fatter, or just go crazy. This then gets blended back to your "dry" signal and the parallel chain is complete.
This parallel thinking doesn’t have to be exclusive to compression, but can also be used for EQ, FX or anything else you can think of.
Now, the big question, why should you use it?
It all depends on what you desire and hear in your head. Do you want something to be more exciting, fat or distorted? These can be awfully vague terms and also very personal, therefore, I have provided some sound examples below that will help you to understand what these sound like. Check it out!
First, a dry drum kit and a dry vocal performance (vocals are from the band The Brew with their song What I Want. Available from Mixing Secrets For The Small Studio By Mike Senior website)
In the next two examples listen to the length of the kick drum and snare drum as well as the thickness of the vocals.
How do they compare to the dry examples? Does it feel fatter?
In the next two examples listen to the attack, or transient, of the instruments.
Do they feel more in your face than the dry examples?
Pretty neat, right?
Internalise these sounds, and note down how the different examples sounded to you. Hopefully, this will help you associate what the different terms, such as what fatter and more attack sounds like.
You can also abuse your compressor and create some nice low-end distortion as an effect. The Pro Tools Dyn3 Compressor is particularly good at this. Check it out below.
Pretty cool and perfect to use to add some grit to your sound.
Having heard all of the above examples you can start asking yourself, "Do I want my drums, bass, vocals, etc, to feel fatter, or have more Attack?"
Maybe you want both? Maybe you want them to be distorted, too? These are just a few questions that you might ask yourself before applying any parallel compression, but ever so important to do so you know why you want to use it.
Of course, the options are not limited to just making things fatter or punchier, you can also make things pump or breathe to create excitement.
Useful tips and tricks to get you started
However, and as I know from my own experience, it’s not always as easy as it sounds, especially when it comes to compression, so in this section I have provided some useful tips that will help you apply your thinking to the most important controls on your compressor which will allow you to dial in your desired sound.
Let’s go over the most common controls you will find on a compressor and why they will help you achieve your desired sound in a parallel setup:
Release: The amount of time it takes for a compressor to return to its normal gain-before-threshold level. The perfect control, together with the Attack control, to create fatness by extending the tail of a sound, that is, applying a longer release time (as heard in the example above).
Attack: How fast the compressor will apply gain reduction after the signal has passed the threshold. Slower attack settings will allow more of the transients to pass through unaffected by gain reduction, giving us more attack (as heard in the example above).
These two controls will give you most of the power you need to achieve your desired sound. And the good thing is, doing parallel compression, is that we don’t have to be subtle in how we shape the sound because it’s getting blended black in.
How to set up your compressor for fatness
Based on what you heard in the first examples you know we are looking for a longer tail and from the description above you know that the Release control will be our friend. Having said that, it’s important to understand that the Release controls best friend is the Attack control and these two needs to interplay together.
The interplay between the attack and the release knob is worth experimenting with to find out what works for the material you are putting through it. Below you can listen to some examples where the only thing that’s changing is the attack time to hear how that can help us fine-tune the tail (fatness) of the instrument.
In this instance, although very subtle, I find that the Fast attack Slow release helps extend the tail (fatness) a bit more.
How to set up your compressor for more attack
Go back to the first audio examples and listen to the `more attack sound, remember how it felt. Based on what you learned from the above description you know we are looking for a slower attack. Again, the interplay between the attack knob and release knob is important here as you will here below.
In this instance, the clear winner for me is the Slow Attack Fast Release that wins if the goal is to create more attack.
Having an understanding as to what you can achieve with parallel compression will enable you to know why you should use it and not just put in on, for example, your drums just for the sake of it. I hope the audio examples and how to dial in your compressor will allow you to get your desired result quicker and give you a deeper understanding of what the controls can do. There’s so much you can experiment with in this area with all the various compressors that are available, so I encourage you to do some playing around in your DAW and find come cool sounds.