Photo by Thomas Aeschleman on Unsplash
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What’s so great about mix depth?
For the clarity of this discussion, ‘mix depth’ is about creating 3-dimensional space in the mixing soundstage.
A music mix with great depth has a wonderful translucent quality, enabling the listener to literally hear ‘into’ the mix. Musical elements have a 3-dimensional placement in the sound-stage where the listener can hear the space around each instrument. This creates a sort of separation between elements, ultimately contributing to a mix with greater clarity.Mixes with great depth simply have a bigger mixing soundstage to work in. This enables more placement options for mixing engineers because they are not confined to panning as the primary placement method. Deep mixes generally have a smoother sound due to the natural reduction in transients of distant elements. Distant miking techniques often sound clearer than close miking due to less proximity effect.
Interestingly, the sparser the mix, the more that depth is distinct in the mix. This is because the perception of depth is audible from the lower-level ambience. In other words, less cluttered mixes can sound huge and deep due to the limited number of elements in a large mix space.
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| Image 01: The mix-space, or mixing sound-stage |
Like A Stone (Audioslave) is a great example of a simple and uncluttered arrangement with plenty of depth.
Also, check out Glass Hammer’s, ‘Lure of Dreams’ for another example of lots of depth in a mix. Pay attention to the relative depth positions of the lead vocals, guitars, and drums. IN the case of the drums, notice how the dry kick and snare levels are brought to the front of the mix-space while the remaining drum kit sits right back in the mix - beautiful!
What’s so bad about shallow mixes?
Shallow mixes have limited depth that often results in a flat, two-dimensional listening experience. It’s like the sounds are cardboard cut-outs stuck on a wall in front of you. Shallow mixes have a limited mix-space and can easily become cluttered if they are too busy because panning is the primary method for placement of an element. These types of mixes can sound overly ‘spikey’ due to the excessive transients and limited spatial information that is caused by the modern preoccupation with close-miking. Close-miking introduces proximity effect that results in a bass bump in the recording, So, if you’ve got lots of close-miked instrument tracks, then it’s no wonder that your mix is getting muddy!
It ain’t about analogue goodness
True mix depth does not come from having tubes and hardware simulations, despite what gear and plugin marketeers will have you believe. It doesn’t come with plugin clones of Fairchild compressors or Pultec EQs. It doesn’t. While the right dose of analogue goodness almost always improves the tonal character of a musical element or overall mix, none of this will help you achieve depth placement of individual instruments, or contribute to a deep mix. The depth-perception comes from the early reflections created by room ambience.
The characteristics of deep and shallow mixes
An instrument that is miked at a close distance (e.g. 150 mm/6” away with a single large diaphragm condenser mic in cardioid mode) creates a recording with plenty of detailed highs and a bass bump due to the natural proximity effect of close-miking. Transients are emphasised due to the closeness to the source to the microphone. The spatial ambience is minimised due to the comparatively high level of the close-miked source. In short, you’ve got a dry and detailed, bass-heavy recording. Miking this instrument close up simulates the human ear hearing it at the same distance. It’s obvious that such a recording would have absolute minimal depth.
In comparison, when the same source is miked from a distance (e.g. 1-2 m/3-6 feet or more, with a single LDC/cardioid), the tone changes dramatically. High frequencies diminish slightly due to the natural dampening effect of sound travelling over distance. The bass bump all but disappears due to no microphone proximity effect. As the mic distance increases from the source, more of the body of the instrument is captured, altering its recorded tonal character. The instrument’s natural tone is also coloured by reflections from nearby surfaces, where the absorption and reflectivity of the surfaces vary across the frequency spectrum (e.g. high frequencies being absorbed by carpet and resonances occurring at varying frequencies). The dynamics are altered, causing transients to be reduced (natural compression caused by the natural resistance as sound travels a greater distance through the air). Room ambience becomes more prominent in the recording. These spatial cues are relative to the size of the recording space, the microphone’s distance from the source, and the reflective nature of the surfaces.
In short, a recorded source sounds vastly different depending on the microphone type, recording distance, and space it was recorded in. Even as a mono recording (as described above) the tonal changes and depth are clearly captured. If the instrument was miked at a distance using a stereo pair of mics, the difference in depth, tone, and left-right placement would be significantly improved, and the recording would take on a beautiful depth and richness.
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| Image 2: close miking vs distant miking In this image, two types of microphone technique are used to record an acoustic guitar in a small recording space. A single close-mic captures a full and transient-rich recording with very little ambience, while a distant stereo pair capture mostly room ambience. A recording set up like this enables many options to control the depth of the element in the final mix. |
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Image 3: wave-forms of a recorded source This image shows how the recorded waveform can vary on the same source. The close-miked source (dashed) has a large transient spike at the start of the waveform and then decays. The distant miked waveform has lost much of the initial transient and has a longer decay due to the increase in room reflections that occur for a slightly longer duration. |
What causes a mix to sound flat and one dimensional?
The modern pre-occupation with close-miking means that many elements are often fighting for position at the front of the mix. Considering that DAWs offer almost unlimited track-counts, it’s no surprise that mixes can easily become cluttered and flat-sounding; too many elements fighting for limited real-estate.
When the engineer attempts to add depth to elements in these recordings by piling on the reverb, all he/she gets is a present up-front sounding element with a reverb wash on it. This approach simply doesn’t sound right. Why? Because the auditory features of a nearby element are still present: emphasised transients, full frequency extension, and limited spatial cues…except now with a dollop of reverb. In other words, washing your close-miked tracks with reverb doesn’t give those elements depth.
The main reason for flat-sounding mixes is that the depth component is missing. Depth in the mix comes from a variety of musical elements placed around the soundstage, but you have to have a soundstage, to begin with. To get that sound convincingly, you need to record your instruments at different distances, ideally in a good-sounding room using a combination of close-miking (single mic) and distance-miking (stereo pair). Alternatively, and with some skill, you can convincingly manipulate the sound of your close-miked elements using hardware and plugins. More on this coming up.
Left-to-right placement (panoramic placement) needs to be done with care if it’s to be done convincingly. Because naturally, our ears and brains locate sound sources by volume and very short delays, whereas your DAW or console uses a volume difference only (panning knob). In other words, placing elements in the soundstage by panning alone is rarely convincing if you’re aiming to locate an element to one side and back in the mix.
How to create depth in the mix
At least one famous mixing engineer has said, “if you want a deep mix, then record it that way.” In other words, microphone choice and placement play a major role in achieving a deep and spacious mix.
Once you understand how mic-to-source distance changes the tonality and depth of a sound source, you can convincingly add depth to the instrument either during the recording stage, or during mixing (e.g. by careful use of dynamics, equalisation, and spatial effects).
Creating depth during the recording process requires careful microphone choice, careful miking distances, a good-sounding room, and a good-sounding recording chain. It can work just as well to multi-track instruments separately or record a band together.
Artificially creating depth using plugins is not easy to do convincingly, and it has its drawbacks; a common problem being unmusical phase anomalies caused by poor plugin delay compensation. But more so, the engineer not treating the element with the correctly to simulate depth.
If you really want to create a massive sense of depth in the mix then try this: mix a song with a great arrangement and a limited number of musical elements. If you combine only a few elements with careful depth placement, then your mix can achieve that holographic and translucent quality where you can almost ‘hear into the mix.’ Remember that the more elements you add, the more frequency masking will occur, and the more blurred the sound will become.
5 ways to create depth in a mix
1. Manage the transients
Close-sounding elements in the mix are transient-rich, while transients reduce more as the element moves to the back of the soundstage. SPL’s Transient Designer can reduce transients just as well as it can boost. You can also use a compressor with a fast attack to grab and reduce the initial transient.
2. Control the highs and lows
Sound sources that are further from the listener have a reduction in high and low frequencies and this varies relative to the source, space and distance. To create distance, use equalisation to roll off some of the high and low frequencies. Shelving filters tend to sound more natural than high-pass and low-pass filters. Look to minimise the low-frequency bump caused by the proximity effect. Don’t be too heavy-handed.
3. Control the room ambience to create depth
Ambience increases as the sound source gets further away from the listener. Decide on three depth positions for your mix, and then use these to place elements close, middle, or distant. Focus on room ambience and early reflections as your primary method to create depth placement for your sound sources. This approach simulates sound bouncing off a wall. Big washy reverbs tend to place elements far back in the mix. Important: to achieve great sounding ambience, you must reduce the dry signal somewhat otherwise the element will still sound close to the listener.
4. Wet your close and dry elements
Adding a little ambience to your close-elements keeps can sound great while keeping them up front in the mix. The trick is to ensure that all the features of a close-sounding element are still present (strong transients, proximity, full frequency range). Then, ensure that your ambient effects are minimal, e.g. a low level of big reverb wash, or a small blend of room ambience.
5. Plan your projects early
I use a series of three sketches to map out a full mix. These are invaluable for managing frequency spread, panning, and depth. The example below shows a depth map (which also includes panning positions). It’s a great way to visually place your mix elements using panning and depth positioning.
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Image 4: Mix Map I make one of these up for every mix I do. It only takes a few minutes. It's a great tool to help you pause and think about the mix. |
Depth-charge Your Mix: Part 2
Check out part 2 of this blog, where I'll provide real song mix examples. I'll break down a mix into separate stems so that you can really hear how the different elements combine to create great mix-depth. I'll also include a mix map (like the one above) to show how I plan the mix.
If you want to check out more mixing tips, grab a copy of my book, 56 Mix Tips for the Small RecordingStudio (tip #35) Available in Kindle or print.
Thanks for listening.
Amos Clarke
