Pro Audio Files

Tips for Using Parallel Compression in a Mix

Transcript
Hi, this is Justin Colletti from Sonic Scoop coming at you from Joe Lambert Mastering.

Today, thanks to B&H, we get to bring you a completely free three-part series on intermediate and advanced compression techniques. We’re not going to be talking about just the basics of compression, but really diving in deep to look at some best practices when it comes to parallel compression, serial compression, and sidechain compression.

I think this one is going to be a lot of fun, so let’s dive right in. First up, parallel compression.

The idea behind parallel compression is you’re going to take a track and split it in two, and one version of this track, you’ll leave completely untouched when it comes to compression, and the other version of this track, you’ll compress pretty heavily. So parallel compression is going to try to help give us the best of both worlds here, allowing us to get the kind of dynamic, human performance out of an uncompressed track, with all of the transient information and breath and life, and then to get some extra oomph and impact out of our compressed track, folding just a bit of that in underneath.

This can be a really powerful technique, and it’s one that a lot of great mixers use very often, and I want to show you not just how to do this, but a few best practices on how to do it really, really well to get really great results. So let’s dive right in to this one.

Today, I’ve got a mix up from friends and clients of mine over at DeGraw Sound. Really great studio in Park Slope, Brooklyn. This track sounds pretty amazing as it is, without any additional mixing. Just kind of faders at zero, so this is going to make our jobs a lot easier, but these same techniques apply on any tracks you get, whatever kind of state of repair they’re in.

Let’s hear this one. Pretty good balances.

[mix]

Really nice so far. Let’s jump in a little bit further, maybe into one of the later choruses.

[mix, chorus]

Man, again, already, really great balance established here from the beginning, but I think we can add more impact, particularly to some of these percussion elements. The percussion elements sound pretty great as is, but let’s hear them by themselves. Here’s just the drums.

[drums]

Pretty good. It looks like with these natural drum tracks, they’ve even given us the option of adding in some kind of sampled drums that are playing in the same rhythm.

So here’s our natural drums…

[natural drums]

And now with our sampled drums added in.

[mixed drums]

So you can hear me taking that last track in and out. The sampled drums. Those do add some oomph, and add some power and impact to the drums, but I think we can do even better still by doing some parallel compression on these drums.

Right now, we’d be focusing on drums and only drums, but generally when I’m mixing, I’ll do all of this in context. I generally want to hear the whole band while I’m making these changes. But just so that you can hear them really well, I’m going to isolate out the drums for this example.

Alright, so let’s get a parallel track setup.

The first thing to do to setup our parallel track is to create two stereo auxiliary tracks that we can route these drums to. So to create these stereo tracks, I’m going to go Track, New. I’m going to create a stereo aux input. You can do this even quicker with some key commands. In Pro Tools, Shift+Command+N will bring that right up. Command+Down will change us to an aux input. Command+Right input changes it to stereo. Hey, check it out. Even faster.

So to set this up for parallel compression, the next thing that I want to do is make sure that all of these drum tracks are getting sent to both of these busses, and then I’m going to compress one of these busses, and leave the other one completely uncompressed. The best way to do that is I’m going to highlight all of my drum tracks here. I’ll highlight the one in the bottom, our last drum track, the room, and then come up here to the kick, highlight that one, great, and now in Pro Tools, I can hit Shift+Option, and change my output path to buss 1-2.

Great. So now all of these drum tracks are being sent out through buss 1-2. Now, I’m going to setup the input on both of these aux tracks to buss 1-2. So all of my drums are going to both of these busses. Here, I’ll name this first one, “drum buss,” and then I’ll name this second one, “parallel drums.”

We’re going to compress the second track, parallel drums. Real quick thing I’m going to do here is I’m going to solo safe these tracks, and when I solo the drums, I can still hear my drum tracks through these busses. So I’m going to hit command and click the solo button, and this will allow me to hear what’s coming through these busses, even when I have the drums soloed.

Great, let’s hear these natural drums again.

[natural drums]

Alright. Now, I’m going to turn on this parallel drum buss, and I’m going to add a compressor to this parallel drum buss to make things really easy to follow along yourself, I’m going to show you that you can do this just using the stock plugins. So we’re going to use, today, just the basic Dynamics III Compressor/Limiter built into Pro Tools.

So I’m bringing this guy up. I’ll mute my regular buss and just listen to the parallel buss for now, for this example. I find that the best way to approach parallel compression is to go A, for a lot of compression, B, use a really fast attack time, and C, do a big, heavy dose of bass and treble boost.

Now, we’ll get to that in a second, but this is an old technique called, “New York style compression.” It’s still popular to this day, and I think you get the most out of parallel compression when you’re compressing with a fast attack time. This is because the whole point of our main, uncompressed track is to let those transients through.

Well, the whole point of our compressed track is to kind of level off those transients, so each kick and snare hit is really, really even in our compressed track, but we get that kind of natural dynamics and transients out of our main track. So we’re looking to get really even transients out of our parallel track to fold in underneath the more flexible and varying transients of our main track.

So to do this, I’m setting a really fast attack time, set a really fast release, and I’ll try to get a lot of compression. I’m talking about 10dB of compression or more. Let’s hear how that sounds.

[drums, compressed]

So it looks like on the gain reduction meter here, I’m getting between 12 and 18dB of gain reduction. Let’s hear this before and after compression. Here it is uncompressed.

[drums, uncompressed]

And now, with the compression on.

[drums, compressed]

Wow, pretty dramatic effect, right? I mean, these sound like machine drums on steroids. If this was our only source of drums in the track, it might sound a little too artificial, and a bit uninteresting, but if we can bring these in, just a little bit under our main track, I think we’re going to hear some tremendous benefit.

Another thing I want to do is add that big bass and treble boost I was talking about. This way, we’re not cluttering up our uncompressed drums by adding a whole lot of mid-range. When we compress a signal really heavily, we’re generally accentuating the mid-range. So to accommodate for that, we’re going to add an EQ after this compressor to boost the lows and boost the highs. I’m talking about by a lot. Like, 10dB. 10dB boost at 100Hz, 10dB boost at 10kHz, but we’re only going to fold a little bit of this resulting radical sound underneath our main drums.

Let’s try that EQ.

So once again, to add this EQ, I’m going to use a stock Pro Tools plugin. Just the EQ III 7-Band plugin built into Pro Tools, and we’re going to go straight for 100Hz here, and boost it a lot. 10dB. Then I’m going to come here to our high shelving filter and put it at 10kHz, and boost that by about 10dB. This is going to be a pretty dramatic effect. Let’s hear first without this EQ added.

[drums, no EQ]

And now, with it added on.

[drums, with EQ]

Wow, that’s a pretty dramatic effect, but we’re just going to be tucking in a little bit of this underneath the uncompressed track, which allows us to kind of get away with even more boost. Now, the reason we’re doing this is to make sure our parallel uncompressed track doesn’t clutter up the mid-range, and instead adds a little weight to the low end, and a little bit of clarity and sparkle to the top.

So let’s go back and hear our drums one more time. This time, the raw, uncompressed track, and then we’ll fold in just a little bit of this compressed and EQ’d track.

[raw drums, then bringing in parallel track]

So you hear how that adds some real weight. I’m actually boosting these parallel drums a bit more than I might need to, but you’ll see these are already pretty low. They’re 12dB lower than the main drums. But I also think we’ll get a pretty nice effect if it’s all the way down here at say, -18dB. Much lower than our mains.

So here it is again with just the dry drums, then with a parallel compress added in, just a little bit.

[dry drums, then with parallel processing]

Now, this might be a little much for you still. One of the things I might look at doing would be to add a high pass filter to this parallel drum track. That’s going to take out the lowest of the low frequencies to get rid of some of the additional clutter we’ve added.

Now, when you’re doing parallel processing, your high pass and low pass filters won’t necessarily respond exactly the way that you expect, due to the phase shift effect of EQ. The phase shift that’s induced in a traditional EQ, like EQ III, doesn’t really have a big effect when we’re just boosting or cutting with a peaking filter or the shelving filter, but as soon as we go to a high cut or a low cut filter, even though I might type in, say, 40Hz here, the actual cut we hear may end up being a little higher than 40Hz. We may be cutting out signal a little higher than 40Hz, based on the phase shift.

That’s a very technical idea, and we can go into that in some depth in the future, but long story short, when you do parallel processing, you don’t really have to worry about the phase shift from EQ, except when you’re doing high cuts and low cuts, at which point, use your ears and don’t look at the numbers, because the numbers can be misleading.

So let’s hear this now with a low cut or high pass filter engaged.

[drums, with filters]

Cool. So that’s another setting that you could potentially play around with, if your drums now started to step on other low frequency instruments, or if you got too much low frequency build up.

Of course, another option is just do a little bit less low frequency boost, but the ideas here are very simple. All we did was take our compressor and set a very fast attack time, and a pretty fast release time. Then, we brought down our threshold to regain that 10-12dB of compression, and then we adjusted our makeup gain to compensate for the amount of level we’re bringing down our compressor.

Honestly, in most parallel compression situations, I’d probably use a slightly higher ratio than I have here at three to one. So let’s play around with these settings and see if we can get even more compression happening. We’re going to start first off with just our plain drums, no compression.

[drums, raw]

Add in our compressor.

[drums, compressed]

That’s mean. Let’s try this with an even higher ratio. Try to switch from three to one, to say, eight to one.

[drums, compressed at eight to one ratio]

That sounds pretty demented by itself. It’s going to sound even more demented when I add in this EQ curve, where we’re boosting the low end, boosting the high end, and maybe cutting just a little bit of the extreme, extreme lows, so that we don’t get too bulky on this one. Let’s hear how that sounds.

[drums, compressed and EQ’d]

Pretty savage, right? But now, let’s go back to our dry, uncompressed drums, bring our parallel buss all the way down to zero, and just fold in a little bit.

[drums, raw, slowly bringing in parallel drums]

Now remember, I’m exaggerating these settings just a little bit for the educational context here, but that said, you can go pretty extreme. It’s allowed.

When you’re making these changes, I would recommend doing it in context with the entire track, and not just listening to your parallel compressed tracks alone in isolation like we are now.

So let’s just do one more quick pass, and make sure we’re really adding something when it comes to hearing this stuff in context with the rest of the band. So I’m going to close out these settings, and let’s go ahead and listen.

Starting with just the uncompressed drums, and then folding in a little bit of parallel compressed drums.

[mix, adjusting parallel compressed drums level]

Again, there I really jacked them up so you can hear how intense this stuff would be if we went full throttle with our parallel compressed tracks, but I think you can hear that sense of extra weight and thunder added into the track with these parallel compressed drums when they’re done with a very fast attack time, and a good healthy boost to the low end and the high end.

Often, you could do big cuts to the mid-range, but in this context, I find the low and high end boost more satisfying and more fun. It’s so rare that we get to boost indiscriminately and not have to feel guilty about it in mixing, but this is one of those cases where feel free to go wild.

This same technique can also apply when it comes to things like bass. Here, I’ll leave our parallel track muted, but something that a lot of folks do with their bass tracks is to split them, and distort kind of one half. Maybe just the high frequency half, leaving the lower frequencies undistorted.

So let’s try out the same idea with bass. This time, I’m going to create a mono aux input, and I’ll create two of them, and now I’ll send our bass out through, let’s say, just buss number three, and I will set the input for our bass busses to be buss number three. It’s always a great idea to name these things.

I’ll solo safe these tracks, once again. And now, this time, I’m going to apply EQ to both of these tracks. My parallel bass buss, I’ll only include the higher frequencies. Say, those frequencies 500, 800, 1kHz and above, and just affect those frequencies at that 500, or maybe 1kHz and above. Just our upper frequencies, and we’re just going to compress and distort those for a little extra added hair.

So let me pull this up here for a moment, just our parallel bass buss.

[bass]

Alright, and let’s try adding some hair to that sound. This time, I’m going to try to find a fun distortion plugin. We’ll go here under harmonic and see what we can grab. Ah, there’s some really great stuff in here. I love this one, the Decapitator by SoundToys, but let’s just use our built in AIR Distortion, and apply it to the bass buss.

[bass, filtered and distorted]

So let’s take this now and fold it in under our main bass. Here’s first, our bass without any processing, and then adding in a little bit of this high frequency distorted bass.

[bass, raw, then adding in parallel distorted bass]

Now here, a little bit goes a long way, but I think we’ll get even better results if we compress both of these basses, just a little bit. First, let’s grab a compressor for our main bass buss. Now, again, in a real world mix, the best way to do all of this is in context. You don’t want to play around with this stuff in solo like I am right now, so if you are mixing this way, get out of the habit of it fast. This again is just for kind of educational purposes, just so you can kind of hear these effects at an extreme.

I do recommend you play around with these effects at the extreme to hear what they do, but when it comes to mixing, you’re trying to train your ear for subtlety. So just add these in to the mix when everything is playing in context.

So let’s try that now. Here’s our main bass with everything else, none of the parallel distorted bass.

[mix]

Pretty subtle, and you can really hear that bass line as is. Let’s start folding in some of this compressed, distorted parallel bass. Just the high frequency hair being added.

[mix, adding in parallel bass]

So we’ve added a lot of weight and articulation and impact, just by making some very subtle tweaks.

Now, are these the final places that I’d wind up? No, not necessarily, I’m trying to make some very extreme moves and some very subtle moves to help you kind of hear these differences, but I want you to start experimenting with these yourself. Open up your own session, whether you’re in Pro Tools, or Logic, or Nuendo, or Cubase, or Cakewalk, whatever you might be using, and try some parallel processing on your drums. Also try it maybe on your bass, and remember, parallel processing doesn’t just have to be about parallel compression. You can also do parallel EQ or parallel harmonic distortion. Parallel effects.

One important thing to remember here is you’ll want to have delay compensation turned on if you don’t already. Without delay compensation, you can get significant phasing issues as you try some of these approaches, but remember, other instruments besides just drums and bass can benefit from parallel compression.

In fact, back in the Motown days, the Motown engineers often used parallel processing on vocals, doing some kind of heavy compression and an addition of high frequencies to the lead vocal tracks. They found this was a great way to preserve some of the natural dynamics and human feel of the main track, while adding in just a little bit of processed sheen underneath.

These parallel strategies can be very effective, and very fun approach to adding tone, clarity, and power to your mixes.

Well, I hope this was a useful exercise for you guys. It’s been fun going through this stuff with you and fun working on this track. So tune in next time when we go more in depth to serial compression and sidechain compression.

If you want more great free tips and tutorials like these, go to B&H, sign up for their newsletter in the audio section there, go to sonicscoop.com, sign up for our newsletter. We’ll keep you abreast of what’s going on on the site, new video content as it comes out, new articles.

So thanks again. This has been Justin Colletti of Sonic Scoop, we’re at Joe Lambert Mastering. I’m coming at your courtesy of B&H. Thanks for hanging out with me on the video blog. See you next time!

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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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