(This is part 6 of a 6-part series by staff engineer Justin Colletti. Check out part 1 on bass management, part 2 on high frequencies, part 3 on bus compression, part 4 on panning for width, part 5 on depth, and part 6 on getting better balances.)
“Depth”, the front-to-back dimension in your mix, is another area where your mastering engineer coax out a lot of hidden magic. But as always, we can do the most enhance the sense of depth in your mixes when there is some of it there to begin with!
To bake plenty of depth into your mix, you first have to realize that not every sound should feel like it’s glued to the front edge of the speakers. And once again, contrast is key for crafting a bold mix that feels like it lives and breathes in all 3 dimensions. Because when every sound is up-front, nothing gets to take center stage.
Once you’ve internalized this idea, the second step is to master the specific tools and techniques that will allow you to bring some sounds closer, and push others back. Judicious use of reverbs, delays, compression and EQ can be crucial in making some elements seem to step back, while allowing other, more central elements to step forward. So let’s get to it:
EQing for Depth
EQ is a surprisingly powerful tool for creating depth. You can use it to push sounds back, or pull them forward.
As a general rule, if you take off some top-end, sounds will feel more distant, and if you add some highs on, they will sound closer-up.
There’s a very good psychoacoustic reason for this: As sound travels through the air, the highest frequencies are attenuated more readily, and the lower ones have an easier time making it all the way to your ear. The distant you are from a sound, the more the high frequencies will lose their energy by the time they reach you.
So, shave off a little of the extreme top-end, and a sound will seem to shift slightly back, deeper into the speakers. Add a bit more, and it will feel like it steps forward.
With this in mind, there’s no question why mixers often like to give vocals a bit of a high-frequency boost, letting the singer to step up in the mix and take center stage. Similarly, percussion elements that are meant to sound up-close and central to the rhythm can sometimes benefit from allowing the highs to come through intact and shine.
But be careful, because there’s always the danger of having “too much of a good thing”. If you end up with a bit of a karaoke-sounding vocal, or cymbals that step right up to the front edge of the speakers, detracting from more important elements in the mix, a gentle reduction or roll-off toward the top can help them sit back slightly into the speakers. Don’t be afraid boost, but also never be afraid to cut highs to taste.
And if you ever want to go really extreme? Using a lot of high-frequency roll-off can help make a sound feel like it’s coming from a great distance—or even from behind a curtain or a wall. The more gradual the slope, the more you will get a sense of subtle distance. The steeper the slope, the more you will get a feeling of outright obstruction by some massive object.
The specific numbers aren’t important, but in general, playing with anything from 5k on up to 15k and beyond can help you adjust the sense of depth without losing too much intelligibility. The higher your boosts and cuts start, the more subtle they will be. So whether looking for distance or immediacy, start higher up, and move lower if you’re not getting the results you need.
The short version?
1) Adding high-frequencies can make sounds feel closer-up, reducing the highs can make them feel further away.
2) Shallower roll-offs and higher-high-frequencies can be more subtle, steeper roll-offs and lower-high-frequencies can be more extreme.
Reverb for Depth
Duh. You can use reverb to make things sound farther away. But there is a bit more art and science to it than that.
First of all, shorter reverbs can help push sounds back slightly and add a sense of “space” around them. But it’s the longer reverbs that can really help push things back even further.
In general, short room or plate reverbs are good to use on elements that want to sound close, but still natural and interesting. Longer halls, plates or chambers are often better for adding a real sense of distance.
It’s not quite that simple however. You’ve also got other factors to play with, most importantly “pre-delay”, “early reflections” and reverb “damping” or EQ.
“Pre-delay” is the amount of time that passes between you hearing the direct signal and the reverb tail.
Less pre-delay gives you a direct sound that arrives at roughly the same time as the reverb tail, and it will make things sound relatively more syrupy and further away.
Meanwhile, adding more pre-delay does two very different things at once: It will give you a direct sound that strikes you noticeably sooner than the reverb tail making the initial impact of the sound seem closer than the alternative. But it will also make the reverb tail feel more distant and massive. This can give a sense of real closeness, but within a much larger space.
There’s a good psychoacoustic reason for this too: Imagine standing in a cathedral and hitting a snare drum. If it’s close to you, you’ll hear the direct sound quite a bit before all the reflections from the far walls reach you. If it’s farther from you, the sound of the drum and the reflections which reach you much closer to the same time. That’s what you’re playing with when you adjust pre-delay.
You can make similar adjustments by tweaking the “early reflections” in your reverb.
Whether you’re in our imaginary cathedral, or hearing someone yell through a bullhorn at the other end of an imaginary football field , you’ll hear fewer “early reflections”—those very quick, tight, initial repeats from the first few bounces of sound off the walls. On the other hand, in a smaller room, the reverberance is likely to be dominated by these initial early reflections.
So, as a general rule, the more early reflections you have, the closer an element will sound, and the fewer earlier reflections, the further away it will feel.
Lastly, there’s the impact of reverb “damping“, which refers to which frequencies are accentuated or minimized in the reverb.
This can have a significant impact on perceived distance, and so can outright EQ on the reverb send or return. Once again, the brighter the closer, and the darker, the further away.
Playing with these settings can help you move sounds forward or backward. But just as importantly, knowing how these settings work can help you get maximum results with a minimum of muck.
To recap:
1) Shorter reverbs will sound closer than longer reverbs.
2) Longer pre-delays will make the initial impact sound closer than shorter pre-delays.
3) More early reflections will make a sound feel closer than fewer early reflections.
4) Brighter reverbs will sound closer than darker reverbs.
Delay for Depth
The same principles that apply to reverb also apply to delay:
1) Shorter repeats will sound closer than longer repeats.
2) Brighter repeats will sound closer than darker repeats.
3) More repeats will help a sound melt into the distance in a way that fewer repeats never will.
Use these principles to your advantage. An added benefit of delay is that you can add distance in very subtle ways, and in ways that enhance the rhythm of the track. You can also get plenty of distance without taking up nearly as much space in the mix as reverbs will eat up.
If you want to keep things tight and pulsating while still effectively playing with the back-front dimension, try delays where you might otherwise reach for a reverb.
Compress For Depth
Your attack and release settings can do a lot to push and pull sounds in the front-back dimension. As a general rule:
1) Faster attack settings subdue your transients and make sounds feel further away.
2) Slower attack settings let the initial impact through, and can make a sound feels like it’s close and coming right at you!
3) Faster release settings bring up the sustain and gritty resonance of a track, making it feel very upfront and immediate.
4) Slower release settings tame sounds further and can help set them further back.
Another effective tool here are transient shapers, which can let you accent the attack for closeness or subdue it for distance. And when all else fails, don’t underestimate the power of sample-enhancement to radically change the apparent front-back position of an instrument.
Summing It Up
So there you have your essential tools and principles. Learning how to use them is not hard. Knowing “when” and “how much” on the other hand? That’s where art and practice come in.
So get twisting, get mixing and try these things for yourself! And when you’ve gotten as far as your mix will go, your mastering engineer is always happy to help coax out additional depth and accentuate the dimensionality that’s hidden deep within your mix.
Just remember that contrast is what allows us to hear clearly, what tickles our ears and what makes for a bold mix. So get out there and think deep!
(This is part 6 of a 6-part series by staff engineer Justin Colletti. Check out part 1 on bass management, part 2 on high frequencies, part 3 on bus compression, part 4 on panning for width, part 5 on depth, and part 6 on getting better balances.)
About Justin Colletti
Justin Colletti is a mastering engineer who is happy to call Joe Lambert Mastering his home away from home. To book time with Joe, Justin or Roman, call or email.