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I think learning how to set a compressor correctly is one of the more difficult things to master because the way it effects the sound can be quite subtle. The key to setting your compressor correctly is to make the changes less subtle (before eventually making them more subtle again.)

Before I get to what I mean by that statement, let me first direct your attention to my last post on the "Importance of Level Matching" because I think it's very important to think about this when setting a compressor. Sure, you can make things "louder" with a compressor but does it really work within the context of the song? There may be some times when you are, in effect, using compression to make a track sound louder but be sure to listen to the difference between using compression and just turning up the volume.

I also think my post before that (on technique being more important than gear) is also relevant here. It may be more relevant when talking about compressors than anything else actually. I believe it's far more important to know how to set your compressor than whether you are using a cheap (or free) compression plugin, a $300 MPA PRO VLA II, or a $4000+ Focusrite Red 3.

OK, now to get to what I mean about setting the compressor so that the changes are more obvious at first so that you can hear what you're doing more clearly. What I do is I think of it as a step by step process where I get each setting (Attack, Release, Ratio, & Threshold) correct one at a time.

The Compression Setting Process

Step One: Set the Release to as fast as it will go, the Ratio to as high as it will go, and the Threshold to where it's very sensitive (where the compressor is working on the input in a significant way.)

Once you've got those three knobs set in this extreme fashion you are ready to start adjusting the Attack knob to where you want it to be. The idea is that the above extreme settings will allow you to hear what's happening when you adjust the Attack much more clearly so that you will be able to get right.

What you will want to do is move the attack faster and slower and listen closely (mixing, when it comes down to it, is all about listening closely) to how it effects the sound. When the attack is faster it will cut out more of the transients and when it's slow more of the transient will get through. Which way you want it to be set depends entirely on the situation.

This is an important point. You need to forget about presets when it comes to compression. They are a waste of time. You need to be listening to how the settings effect what you are doing in each particular situation. The more you do this, the more of a "feel" you will get for getting the sound that you want quickly.

Another point I need to make is that with the extreme settings on the other three knobs, the overall sound of the compression will be really awful, you need to ignore that. Those extreme settings are so you can focus in on the sound of the Attack and how adjusting the attack effects the sound.

Step Two: Once the Attack is set where you want it, it's time to start working on the Release setting. To put it simply the Release is how quickly the compression stops working. This is an important setting as far as how your compressor effects the timing of your track.

The Attack knob tells the compressor how quickly to start compressing (when the sound goes above the Threshold) and the Release knob tells it how quickly to stop compressing the sound after it's been triggered.

Similar to what I said about setting the Attack, when you are setting the Release you need to be listening closely to how it is effecting the music. Forget about presets and try to forget about math (about where it's "supposed" to be set based on BPM or whatever) and try to get a feel for where it releases so that it fits in with the groove of the song. And that doesn't necessarily mean "perfectly in time" either, in fact it pretty much never means that. Don't set it like it's a metronome. That's not groovy.

Step Three: At this point you should have your Attack and Release settings where you want them to be. Now it's time to lower your Ratio knob and lower it until you get it where you want it to be.

One way of approaching this is to lower the Ratio until you no longer hear the effects of the Attack/Release clearly and then to start raising it back up until it's where it sounds just right.

Presets and formulas aren't going to do you much good when trying to set the Ratio. Memorizing that you're supposed to be at 4:1 for this and 2:1 for that may help you get you pretty close to where you want to be, or it may just stop you from doing what you need to be doing most: listening closely.

Step Four: Once you've got your Attack, Release, & Ratio settings right you will be ready for the final step of setting your compressor which is setting the Threshold.

If you followed my advice and set it to be very sensitive then the compressor is probably working pretty much all the time and this is great for being able to hear what you're doing so that you can effectively set the first three knobs but it's probably not what you really want.

You should make the threshold less sensitive until it's higher than you want it to be and then you should lower it until it sounds right (this is sort of like what I just said you should do with the Ratio where you lower it until you don't really hear the effect anymore and then raise it until it's just right.)

It's unlikely that you would want the compression to be on all the time. There should be moments where it's not doing anything (the quieter moments.)

Conclusion

I'm hoping that you find this "process" helpful in opening up your ear. It's really all about allowing you to hear what each setting is doing more clearly so that you can make a more informed decision about where the settings should be to get the sound you want. My motto is that mixing is all about listening closely and I think using this process makes it easier to listen closely to the effects of compression.

Tags: Compression