Pro Audio Files

Tips for Using Serial Compression in a Mix

Hi, this is Justin Colletti from Sonic Scoop, coming at you once again from Joe Lambert Mastering. Once again, thanks to our friends over at B&H, we get to put together another part of this instructional series on intermediate and advanced compression techniques.

In our other installments in this series, we’ve been looking at parallel compression and sidechain compression. This time, we’re going to take a deeper look at serial compression.

Serial compression really just means one compressor feeding into another in series. One after the other. Generally, we’re going to be looking for something slightly different out of each compressor. There’s no rules about how to do this, but here’s some guidelines. Often, you’ll want to put faster compressors before slower compressors, and your higher ratio compressors in front of your lower ratio compressors.

The idea is that if you have a kind of slower, lower ratio compressor second, and a more fairly gentle compressor, you don’t want to accidentally feed it any huge spikes that are going to make that slower compressor kind of overreact and maybe not recover in time. So instead, you might use a higher ratio compressor first to tame peaks before you go into your slower ratio compressor.

You can also do a lot of playing around with the shape and the envelope of the sound by putting your fast compressor first and your slower compressor second. Here’s the idea. Your faster compressors are going to shave off the kind of transient attack on a sound, and this can be a great thing, because a really fast attack time can give you more consistency in each hit, and you can get much more dynamic control.

But too much of this fast attack compressor kind of vibe can leave your sound feeling a little dull and lifeless. On the other hand, a slower compressor can allow a lot of initial attack and a lot of initial transient through. This can add a lot of punch and initial impact to the sound, but with a really slow attack, you might not get a lot of dynamic control. You’re just letting so much of the signal through.

But by stacking a fast compressor first that’s going to shave off your transients and make each impact a little more consistent, you can then take that sound and put it into a slower attack compressor to bring back some of the initial attack. But this time, more consistent than before.

So this way, we can kind of get the best of both worlds. The consistency of a fast attack compressor, and the impact and life and vibrance of a slower attack compressor. Let’s try this out focusing first on drum buss, but you can do this in so many different places. From vocals to guitars, to you name it.

Alright, let’s dive right in. Again, we have a great track here from our friends over at DeGraw Sound. This mix is sounding incredible, even with the faders at zero, but I still think we can do a couple of tricks here and there to get even more out of this track.

So first, let’s go down to our drums and we’ll create a buss for our drums to make sure you can process them all together. I’ll do this by hitting Shift+Command+N. That is my shortcut in Pro Tools for creating a new track. Then, I will create stereo aux inputs. You can also access this from the Track menu here. Track, New.

Same concept applies in any DAW you might be using. Now, I’m going to want to set all of these tracks to come out of the same buss, so I’m going to hold down Shift+Option and select buss 1-2. Holding down Shift+Option while I set my output here will apply that change to all of the selected tracks.

Now, I’m going to take my drum buss, give it a name, and go ahead and set its input to buss 1-2. Last thing I’ll do is solo safe this drum buss. Now, when I solo all of my drums, I’ll be hearing just the drums.


Let’s hear it in the chorus.

[drums, chorus]

Sounds pretty good. Let’s see if we can spice this up with a little bit of compression.

In our parallel compression video, I did compression on a parallel track and left our main track alone. But, just to experiment and get to hear the effects of serial compression, let’s try this on our main track.

I’m going here to our compressor/limiter, and we’re going to start off with a high ratio, fast attack, fast release compressor. This effect will be a little dramatic at first, just so you can hear it.

[drums, compressed]

That’s a little bit much. So let’s back off on this threshold. Hear how it sounds now.

[drums, compressed with adjusted threshold]

Man, this drummer did a pretty great job. These hits are so consistent to begin with, but I think you can get a sense for some of the additional consistency we’re adding with this compressor, and you also get a sense that we’re losing some of the initial attack.

Let’s listen to this one more time with that in mind.

First, without. Then with.

[drums, compressed and uncompressed]

We’re getting a little bit more heft here, but we’re maybe missing some of the clarity and initial impact of the sound. So let’s try to add on another compressor. I’m holding down Option and dragging, just to duplicate this compressor, and this time, let’s add on one that has a really slow attack time and still kind of medium/fast release here, and maybe a bit of a lower ratio.

Let’s hear how this sounds.


Do you hear how some of that initial impact is coming back into the sound when we put on this slow attack compressor? Let’s hear these two different sounds separately from each other. And this is really one of the best ways to learn how to hear compression really, really well is to put on some heavy compression and play around with your attack setting. Get a sense for how it’s changing the shape, and the envelope, and the push and pull of each sound.

So let’s first hear a fast attack compressor, and then we’ll hear the slower attack compressor, each by themselves.

So here it is with a fast attack compressor…

[drums, fast attack]

Great, so we’re adding some heft to the sound, even more consistency, although this drummer is remarkably consistent to begin with, but we’re losing some of that initial impact and attack.

Let’s hear it now with just the slow attack compressor.

[drums, slow attack]

I really think you can hear that most on the snare, how you can get some extra articulation on the snare and some extra crack out of it.

Now, if this drummer was a little inconsistent, and he’s not, the drawback would be that we’re not getting as much dynamic control. So this is one way of thinking about a compressor, or at least the attack on compressors is what portion of the instrument do we need to control? If we need a lot more consistency on the initial hit, we’ll go for fast attack compressor, but if doing that sucks too much life and initial impact down, we can get some of it back and we can accentuate some of that attack that we lose with a slow attack compressor.

So when we put the two together, we can get the stability of a fast attack compressor with the punch and impact and clarity of the slow attack compressor. Let’s hear this one more time, this time, no compressor, then our fast, then our slow, then our fast, and then both together.

Here we go.

[drums, different compressor settings]

Now, that’s an interesting effect. Some of those changes were very rapid and could be very subtle, but I think in the end, you heard us wind up with a sound that’s maybe a little over compressed, and I probably wouldn’t want a sound quite that over compressed on my drum buss, unless it was for special effect.

Alright, so by now, I think you should be starting to get some insights into how some attack times can sound pretty different and how you can stagger your attack times, sometimes feeding a fast attack into a slower attack. That allows you to get the best of both worlds, right? Kind of shaving off some of the initial transients, getting some control on the initial impact, and then going through a slower attack compressor to bring back some of that initial impact.

I recommend that you try some of these techniques for yourself, because that’s the real way to learn.

Another thing to keep in mind is that sometimes, you can have kind of slow and softer ratio compressors that will act really nicely with a lot of sources, but if you hammer them too hard with signal, too hard with peaks, they might not respond in a way that’s consistent.

So often, engineers will sometimes take a faster attack and higher ratio compressor, maybe even a limiter and use that first before going into a slower, more subtle compressor.

Now again, there are no rules. There may be times and places where it makes sense to completely reverse this. It’s not unheard of to put a gentle compressor first, and then feed that gently compressed signal into a limiter. That could work too. Try these things out for yourself, but the most important thing is to know how some of these parameter adjustments are going to affect the signal, and going to affect your sound.

I hope you’ve enjoyed this look at serial compression. This has been Justin Colletti of Sonic Scoop, once again brought to you by our friends at B&H. You want more great videos like this one, you go to B&H, you sign up for their newsletter and mailings there, I’ll be waiting for you in your inbox. Also, be sure to check us out at, sign up for our newsletter, where you’ll get great articles with gear reviews, tutorials, interviews with producers and engineers, and we’ll send you notices whenever we put out new videos like this one with B&H. This is some of our favorite stuff to do.

If you haven’t already, check out the other installments in this series on parallel compression and sidechain compression, and if you ever have any questions, reach out any time.

Thanks again for hanging out with me, I’ll see you next time.

Justin Colletti

Justin Colletti

Justin Colletti has been obsessing about audio for more than 20 years, and working in the field for nearly 15 years. Learn more from Justin in Mixing Breakthroughs.

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