Audio Mixing Bootcamp: How to Set up the Compressor

show more Setting up the compressor provides you with in-depth training on Audio + Music. Taught by Bobby Owsinski as part of the Audio Mixing Bootcamp show less
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Setting up the compressor

In this video we are going to look at how to set up a compressor. I am going to show you how to configure the compressor so it breathes with the track, how to turn it into a limiter, and how to determine how much compression is right for the track. Timing of the attack and release is importance so the compressor works correctly and makes the sound punchy or fatter or makes the note have a longer decay. One of the easiest ways to set that up is to use a snare drum as your template, then use the same approximate Attack or Release settings for the other instruments. The idea is to make the compressor breathe in time with the track.

So the first thing we are going to do is going to go to our snare top mic and add a compressor. In this case, what we are going to do is we're going to put the compressor before the EQ here, and the reason for that is the sound is different if you put the compressor after the EQ. What ends up happening is if you put it afterwards is that anything that's emphasized on the EQ, for instance if 3k is turned up, then that frequency is going to be compressed, and it's going to be emphasized by the compressor as well.

So it usually sounds better if you put the compressor prior to any EQ that you have. If doesn't mean that that's the way it always should be, but most of the time that's the way it looks best. So let's listen to this soloed without any compression at all. Here is the snare drum. (music playing) So now what we want to do is set the compressor up so it breathes with the track. So what we are going to do is we are going to take the Attack and turn it all the way to its longest, and then we are going take the Release and we are going to turn it all the way to its shortest.

Now let's play it again. (music playing) Let's bring the threshold down. (music playing) So we see some compression. Okay there we go. (music playing) So we've got about 6 dB of compression here. I am going to take the attack and I'm going to move it back. I am going to make it shorter. (music playing) Hear how the sound changes? (music playing) We are cutting off the attack on the snare drum, the first part of the sound of the snare drum.

You can see we've got lot more compression as well as we do that. This isn't what we want, because it makes it sound unnatural, so I am going to move this back. We just begin to hear a sound change. (music playing) Somewhere in there is good. (music playing) Going to begin to move that back. (music playing) You can see over here on the Gain reduction meter, this is the amount of compression that we have.

You can see how it's breathing with the track. Let's move this back a little more. (music playing) What we're doing now is we are making the decay longer. (music playing) So it sounds like the decay lasts from one snare hit to the other.

(music playing) Now let's Bypass for a second. (music playing) Really hear the difference there. This is without any compression, and here is with it. (music playing) You can hear how much punchier it is. Let's move this Attack back a little bit more. (music playing) Let's listen in the track, hear what it sounds like.

(music playing) Okay, I am going to play it again. We are going to bypass it this time. (music playing) Now watch the meter here and watch the different levels of hits. I am going to play it again, and watch sometimes it goes -10 and sometimes it goes -6 here. Watch.

(music playing) You see some go -10; some goes little bit higher. And in fact this drummer is actually pretty good, because he is pretty consistent. But what we are trying to go is we are trying to get that snare hit to be the same every time. So now let's play the same thing with the compressor in. (music playing) And that determines how much compression we are going to use.

We are going to use enough that in fact the snare hit in this case is pretty much the same, so it doesn't change that much. You can hear how much more punchy the sound gets though, when we have the compressor in. (music playing) One more time, only Bypass. (music playing) And with compressor in. (music playing) So what will happen here is we'll also do the same thing on the kick drum and we will do it on the bass.

We will probably do it on the guitars. We will do it on the vocals. We will do it on any instrument that has any kind of variation in dynamics, because what we are trying to do is control the dynamics here. You can't make the dynamics completely go away--and you don't want them to--but you don't want the variation to be great as well. If the go, oh, 3 dB either way, that's probably good; if it goes more than that, it's probably too much. Let's try the compressor over on the vocal. Now the first thing we are going to do is we are going to add it in here, and again, this is just a native compressor that comes with Pro Tools.

Don't forget that just about all the parameters are somewhat the same, but even if they're different, it doesn't matter; what we're trying to get is the sound. We are trying to get the compressor to breathe with the track, and that's the most important thing. So let's listen to the vocal without the compressor. (music playing) This is pretty good, because it's actually been compressed when it was recorded, but we can still do a few more things to it.

In this case what we are trying to do is make sure that every word is heard, so we don't want a word to drop out at all; we want them all to be the same. There are some that will drop out anyway that you'll have to use automation and actually goose the fader a little bit so you can hear it, but for the most part we can get most of them with the compressor. So let's set this up. Let's unbypass it. So the first thing what we are going to do is we are going to set our Attack and our Release approximately the same as we did with the snare drum. This might change a little bit, but this is a good starting point.

So I will put 188 in for the Attack, and we will 12.3 in for the Release. And let's dial in the Threshold. The Threshold actually controls at what signal level the compressor is going to begin to work at. And let's move this back, so we can hear it working. (music playing) There we go. We can hear it there. (music playing) Now what's happened here is these Attack and Release settings have to be tweaked because you can hear the change in the vocal sound, and that's not what we want-- we want it as pure as we can get it.

So the first thing we are going to do is back off the Attack a little bit. (music playing) Back off the amount of gain reduction. (music playing) By the way, we are reducing the gain on the peaks, so that's why they call it gain reduction, but it's the same thing as the amount of compression. Here's what it sounds like. (music playing) Okay, let's listen in the track.

(music playing) Okay let's listen without it now. Let's bypass it. (music playing) Here is with it in. (music playing) So you can hear the difference in the vocal with the compression and without the compression.

With compression, it almost sounds like the vocalist is in the room with you; he comes closer to you in the mix. You can hear every single word that happens. In fact, there is a byproduct here. You can keep the vocal lower in the mix and still hear it really well. Without the compressor some of the words of the vocal will drop out and you won't hear them. One of the reasons why we would like to keep the vocal lower in the mix is it emphasizes the power of the band. On a pop record, usually the vocal is really on top of the band; it's really loud compared to the rest of the band.

But if we want the record to sound really powerful, then we would like to keep the vocal down even with the band, and the only way you can do that well is if you compress the vocal; otherwise it will sound weak. So this is what we'll do with all the other instruments that need it as well. We will go and we will listen to them and we will see if there's a big variation in dynamics, and if there is, we will insert a compressor. The amount of compression that we will use is the amount that will keep the dynamics relatively solid so you hear all the chords; there's not one that drops out that we can't quite here.

And that's what gives you the feeling of having the vocal in the room with you. So let's talk about limiting. Right now, we have the Ratio set to 3 to 1, but anytime the Ratio goes beyond 10 to 1, this turns into a limiter; it goes from a compressor into a limiter. Now compression is used to control dynamics. What we are trying to do is take any peaks and bring them down, and we're trying to bring up any of the notes that are getting lost. What we are trying to do with limiting is to keep the next stage in the signal path from distorting.

So in this case what that means is it's going to take 11 dB before even 1 dB comes out, and that will probably mean that we can take any kind of peaks and not have a problem with the stage afterwards distorting. So there's a different mindset with using each of them. Sometimes we use limiting of 11 to 1 or 20 to 1, or even higher, in order to change the sound of an instrument or a vocal. Because usually anything that's 4 or 6 or 8 to 1 is just controlling the dynamics and we don't really hear it work, but anything that goes beyond 10 to 1, we begin to hear the color of the compressor.

Sometimes that's what we want; sometimes it isn't. Okay, let's listen to the difference between compression and limiting. We are going to go back to a ratio of 4 to 1 and have a listen. (music playing) We can hear the sound change, but listen when we go 10 to 1. (music playing) Now all of a sudden the sound of the compressor is what we hear more than sound of the vocal, and it gets more severe as we go.

Let's go to 30 to 1, which is really quite high. Let's listen in the track. (music playing) (music playing) In this case, we can actually hear the compressor working, and what it's doing is its taking some of those peaks and it's actually bringing them down too low.

So the vocal sounds unnatural. That's why we like to use compression rather than limiting most of the time. There are times when limiting is really desirable--for instance, on a bass. The reason why is we want to keep the bass at a pretty solid level. We don't want it to vary too much, because as it varies it makes the song sound not as powerful. It sounds a lot more powerful when the bass is at one level. So that's one time we might use limiting instead of compression. Most of the time would like use compression, though. So that's how to set up the compressor.

You should time the compressor so it breathes with the track by using the Attack and Release controls. An attack that's too fast will dull the sound of the instrument or vocal, while a release that's too short will cause it to pump. A ratio setting of 10 to 1 or more is considered limiting, because it's trying to limit the output rather than control the dynamics. The more compression you use the more you will hear it working, and the amount of compression depends upon the song, the arrangement, the player, the room, the instrument or vocalist, or the sound that you're looking for.

Setting up the compressor
Video duration: 14m 45s 8h 53m Beginner


Setting up the compressor provides you with in-depth training on Audio + Music. Taught by Bobby Owsinski as part of the Audio Mixing Bootcamp

Audio + Music
Pro Tools
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