The Second Leg Of The Stool: Space
Welcome back to my series on mixing! This is the fourth post in a (likely) six post series, so if you haven’t read the preceding posts in this series, Mixing Is A Three Legged Stool, The Seat Of The Stool: How To Listen To Music Like A Mix Engineer, and The First Leg Of The Stool: Volume, then you may want to do that and then return. And with that out of the way, let’s jump in.
First and foremost, it’s important to keep the mindset that mixing is about “making sounds work together at a given point in time,” not “arranging so you have to mix less.” In the first post in this series, I made the point that lots of problems people try to solve in mixing really aren’t best solved by mixing at all, they’re best served by changing arrangements. If the only sound you have playing at a given time is a single guitar, then you don’t need to do any mixing at all. I’m reiterating this here because, in my experience, a lot of people try to use space as a cheap hack for avoiding going back to the arrangement. So, don’t do that. And finally, we’re talking about stereo mixing here, not Atmos or any other surround sound applications or techniques.
Generally speaking, you want to have your volume mixing done (at least to a great draft level) before you move on to space to help avoid using panning as a crutch to overstuff a song.
To recap, space just means where a sound sits in the stereo field, how close or far it feels, and how much real or artificial space surrounds it. When you’re thinking about mixing for space you should primarily be thinking of three things:
Creating a feeling of width or depth
Using spatial motion or placement to draw attention to a part
Placing your song in a shared space so that it sounds like the instruments are physically together and more glued up
We’ll take these in order.
How To Work With Width Or Depth In A Mix
I’m going to start this section by saying that if you’re mixing on headphones, this is going to be a lot harder for you. Headphones are binaural, not stereo, and we humans hear in stereo. There are systems like Slate’s VSX which attempt to remedy this, but appropriate speakers in a well treated room will make your life a lot simpler here.
What Makes Us Perceive Width And Depth Sonically?
There are two functions that affect how we perceive location and size of sounds in a spatial way. Location and width of sounds are primarily sensed by the delay in perception of a sound from one ear to the next. A sound to your right will hit your right ear before the left. We perceive distance or depth largely based on reverberation and EQ rolloff. Sounds that originate far away often sound muffled and more reflected. In short, because the sound has to travel a longer way to reach our ears, you’re hearing more of the effect of the environment on the sound than the direct sound itself.
As we’ve evolved (as a species) and learned (as individuals), we seem to recognize these shifts in sounds intuitively, and can easily infer a lot about the origin of a sound, even if we’re not considering it consciously. However, as humans mixing songs, we have to be a lot more intentional about the process.
How To Adjust The Width Of Sounds In A Mix
Width is largely a function of phase, so be careful, because a sound recorded in (or made) stereo can cause phase cancellation when summed to mono. Try taking a sound in a song and using your DAW’s utility tools to collapse that sound to mono. When you do, some of the sound will almost certainly go away. The parts of the sound that vanish when summed to mono are getting canceled out by inverted phases on the left and right channels.
Many plugins and hardware tools have width knobs to increase or decrease the perceived width of a sound. These tools operate in different ways, but the basic underlying premise is that they exaggerate the variances between the left and right channels to make a sound feel bigger and wider. Often, they use mid and high frequency EQ boosts at slightly different frequencies on the left and right channels paired with very subtle saturation so that the harmonics vary between channels. This creates the psychoacoustic experience of a sound being very wide. The more different the two channels are, the wider the sound feels, up to the point of feeling like two completely different sounds with two different origins.
Many of the SSL channel strips, like the SSL 4K E and SSL 4K G have a simple width knob that creates a widening or narrowing effect on a channel, but you can create a similar effect by using an EQ that allows you to address the left and right channels differently (or using creative send routing to accomplish the same thing). For instance, on your left channel you could apply a wide EQ boost of 2 dB at 800 Hz and a wide EQ boost of 2 dB at 1000 Hz on the right channel for a subtle widening effect. Conversely, if you’re using an EQ with a mid-side function like FabFilter’s Pro-Q 4, you could apply a high-pass filter to the sides at 120 Hz to narrow the bass frequencies of your track or song.
Why Should You Adjust The Width Of A Mix?
Adjusting width can bring sounds to the forefront just like volume can. A sound that feels huge and wide dominates perception, while a sound that is narrower is less overbearing. If you’re working with a sparse mix, making one sound feel enormous is a good way to make the mix feel fuller. On the other hand, if you’re working with a busy, dense mix, paring back the width of individual tracks is a great way to let the listener hear more of what’s going on without feeling overwhelmed.
How To Adjust The Depth And Distance Of Sounds In A Mix
Think of distance and depth as a continuum of EQ, reverb, and delay (or echo). A sound that is very close to you sounds full. You hear the full spectrum of its sound because the high frequency hasn’t been eaten up by the environment. You’ll also hear the original sound well before you hear its reverberations or echoes. A sound that’s far away loses a lot of its high frequency content and sounds highly reflected, often muddy because of the number of echoes that have stacked up along the way to your ears.
If you want a sound to appear more distant, reduce the pre-delay on your reverb, make the reverb much wetter, and roll off the high frequencies of the sound. If you want the sound to appear to be closer to the listener, increase the pre-delay on the reverb, make the reverb a bit drier, roll off the high frequencies of the reverb a touch while boosting them on the dry sound. You can also add a subtle delay to make it feel like the initial dry sound is more up front.
A narrow original sound with wide reverb and delay sounds like a sound that originates close to the listener in a large space. A wide, highly reflected sound with little unprocessed information sounds far away.
As always, check what you’re doing in mono. It’s very, very easy to create unintended phase cancellation that will negatively impact your listeners’ experience. Voxengo Span is free and has a stereo correlation meter you can use to monitor how in or out of phase things are. Stereo correlation meters are easy to read. They typically go from -1.0 to 1.0. A reading of -1.0 is a sound that’s totally out of phase, so it will be silent when collapsed to mono. A reading of 1.0 is a sound that’s totally in phase, so none of it will cancel. You should strive to keep your sounds north of 0.0 most of the time.
Why Should You Adjust Depth And Distance Of Sounds In A Mix?
Often, you shouldn’t. This technique can lead to a really messy mix. But let’s say you’re mixing something you want to sound like a band playing together. Using these techniques subtly can bring realism and life to the recording that will help the listener place the players on a stage or in a room. This technique can also be used for sound effects and samples in a song if you want to give a sense of drama, realism, and interest to a part.
How To Use Spatial Motion Or Placement To Draw Attention To A Part
This part is a lot simpler than width and depth. Space creates separation. Don’t be afraid to hard-pan sounds, especially mono sounds. Hard panning the rhythm guitar to the left, the lead guitar to the right, and the vocals to the center creates separation of those sounds and gives them room to breathe. By using just the pan knobs in your DAW, you can open up songs tremendously. Leaving everything center-panned means that you have a lot more potential for frequency overlaps and buildups that will need to be heavily managed by EQ. The less you EQ or compress a sound, the more like itself it will sound in the end. By giving instruments space in a mix, you need to alter them less.
You can also use panning automation to grab a listener’s attention and place it squarely on a part. If you pingpong a sound from left to right, it becomes very noticeable. If you bring a sound from a side to the center, it immediately takes center stage for the listener. However, if you create too much automated motion, you create a lot of chaos that your listeners will struggle to interpret or, even worse, find unpleasant.
Remember, though, if you hard pan a stereo sound, you are effectively collapsing it down from stereo to mono. Make sure you’re taking into account the phase cancellation you may create.
How To Create Shared Space For All The Parts In A Mix
In years gone by, bands would always perform together, live, for a recording. Engineers would set up as many mics as they had free channels, isolate what they could, and print what was played. While excessive microphone bleed was (and is) a problem for mix engineers, a bit of it created a natural shared space and room mics that captured whole performances really did a lot for placing a performance in a space and making it sound like you were listening to a group of people playing together, not a bunch of unrelated recordings played at the same time.
Today, as solo projects, remote collaboration, and amateur home recording grow in prevalence, recording a band all at once is dramatically less common. And even when bands have the opportunity to track together live in the studio, many often opt for multitracking each part to improve the likelihood of a “flawless” performance.
Music that is recorded and mixed without a sense of space often feels sterile, which can, of course, also be an artistic decision. However, we humans are used to hearing sounds and music that sound like they’re in a place. It helps music (even electronic music) sound more natural and believable to our ears.
Good news: creating a sense of space (either real or artificial) in your mixes isn’t terribly hard to do, although it is an area of mixing where many novices make mistakes. Generally speaking, the simplest way to do this is to create a 100% wet reverb send effect and bus all your tracks (post-fader) through it and adjust the volume of that new track to taste. However, that’s leaving out some nuance that separates amateur sounding mixes from professional ones.
If you’re serious about getting this right, working out the “space” bus early is key. Often, the bus I’ll use is a very subtle slapback delay (which is also part of the sound in many rooms) into a reverb, into an EQ, and finally into a width plugin that allows me to make the low frequencies mono and adjust the width of the mids and highs to taste. If you want a highly realistic reverb, I don’t think you can beat LiquidSonics Seventh Heaven Professional, which is a Bricasti Model 7 emulation. Wave Alchemy’s Magic7 is free Bricasti emulation that also sounds great, but lacks much in terms of flexibility. FabFilter’s Pro-R 2 is another good option. For artificial spaces, the sky is the limit, and there are zillions of great reverb plugins. Wave Alchemy’s Glow, Valhalla’s Super Massive, and many others provide very usable reverbs for mixing. My personal favorite artificial sounding reverb is the Chase Bliss CXM 1978, which is essentially a Lexicon 224 on steroids.
When setting up your reverb, you generally want to set the pre-delay to be short enough so that you don’t get a lot of muddy buildup, especially from your drums, but long enough that the dry sound has a chance to play through first. Thinking of the decay time or reverb tail in terms of note length is often helpful too. There are many free tools available online that can help you figure out how many milliseconds different notes are at different tempos if your reverb plugin only operates in milliseconds (or hertz). A reverb that lasts for 1/4 note will feel fairly long and a reverb that lasts 1/16 note will feel fairly fast. The shorter the reverb, the more constrained a space will feel, and the longer the reverb, the more expansive the space. Consider the energy of the song, its genre, and what sort of space you want to place the song in when you’re deciding how long the reverb should last.
Once you’ve dialed in how you want the reverb to sound, you need to adjust its volume. There are many different philosophies here, but one thing that is very common among novices and people working in untreated studios is reverb that’s too loud. It’s often useful to find the point on the fader where the reverb is barely audible and set the fader just a hair above that level.
Some folks put the reverb on the master bus, and there are times when that can be appropriate (like if using a reverb as a subtle mastering saturator), but for creating a sense of space, I would always recommend making a send effect out of it and bussing your tracks through it. You get far more control of how much of each sound appears in the reverb and you gain more flexibility in how you want the reverb to behave throughout the song. Maybe you want it to bloom out loudly at some point, and that’s much easier to accomplish on a send effect.
In Conclusion…
There’s a lot more to mixing the space in your songs than just twisting the pan knob, but if you learn the fundamentals and learn the tools you have at your disposal deeply, it’s pretty easy to develop a workflow rhythm that creates consistently great results. Don’t be afraid of mono tracks in your songs. Oftentimes, different sounds in mono spaced throughout the mix create a far larger soundstage than lots of stereo tracks, which wind up clashing and causing complex phase cancellation issues.
In the next post, we’ll talk timbre for mixing. See you soon!
