Top-down mixing is a reverse approach where you begin with your stereo bus and work your way to the individual tracks. Learn how to utilize this method for musical sounding mixes, efficient results and less CPU load.
By Charles Hoffman
The great thing about top-down mixing is that it’s slightly unpredictable. You have no way of knowing exactly how the EQ moves you make at a track level will interact with the compressor on your stereo bus unless you experiment; you may find yourself pleasantly surprised.
“Stereo bus processing” is often thought to be synonymous with “mastering,” but that’s not always the case. Traditionally, mastering is the process of creating the master copy of a song, from which all other copies are made. If you apply stereo bus processing to your song without the intention of optimizing the playback of your track for a desired medium, you’re still in the realm of mixing. Many mixers today enjoy using stereo-bus processing even if they know the mastering engineer will add their own flavor.
The general workflow I like to use when performing top-down mixing involves applying processing to my stereo bus, setting rough track levels, applying processing to my sub buses, setting rough track levels again, and then processing individual tracks. Towards the end of this process, I’ll start to incorporate aux tracks containing reverb, delay and other FX.
To help you get the most out of top-down mixing, we’ll be looking at 5 tips to help maximize efficiency while mixing, creatively tone shape your mixes and drastically reduce CPU load. You can expect a few hiccups as you dive into this alternative mixing method and a seemingly unusual workflow. Stick with it, and you’ll quickly begin to wrap your head around top-down mixing.
Relying solely on visual cues for feedback when mixing can be detrimental to a mix. You may think that a vocal requires 2-3 dB of compression, but the type of compressor you’re using and the compression settings can affect how much compression is needed.
In regards to top-down mixing, relying solely on visual cues can be even more of a risk than when mixing bottom-up. The gain-reduction meter of the compressor on your vocal track may be reading out 2-3 dB of reduction, but this signal may be getting compressed even more as it passes through your vocal bus and stereo bus.
You need to develop a different mind-set to mix top-down effectively. Listen closely to how your tools are affecting your sound. Top-down mixing introduces too many levels of processing to rely on visual cues. If it helps, close your eyes when you adjust plugin parameters. Mixing with your ears will allow you to focus on how your processing tools are truly shaping the tone of your mixes, without the destructive influence of visual feedback.
There are two avenues you can take when it comes to your stereo bus processing; you can either mix into your stereo bus, or mix with your stereo bus processing. The first method involves using your stereo bus processing as a wall of responsive color, and the latter method involves immediately adjusting settings at a stereo bus level, right after you set your first round of general track levels when you begin the mix.
As your mix starts to take form, the portion of your mix that you’re satisfied with will likely be reliant upon the processing applied to your stereo bus. If you modify your stereo bus processing partway through mixing your song, you risk throwing off the balance of your mix.
For example, a tape saturator like the J37 Tape is a pretty common plugin to use when performing top-down mixing; it’s full of color. Tape saturators help mellow out top-end harshness, meaning that if multiple elements in your song are reliant upon this taming effect, the removal of this tape saturator could be catastrophic.
It’s a little less risky messing around with the processing on your sub-buses since there are far fewer sounds summing together in comparison to your master bus. You can apply processing to your sub-buses, much like how you would when mixing bottom-up; the same goes for your individual tracks. The main difference is the order in which you apply processing; sub buses first and individual tracks second.
On top of the tone shaping abilities that stereo bus processing brings to your overall mix, it allows you to reduce your computer’s CPU load. One instance of a plugin on your stereo bus is always going to be less CPU intensive than applying duplicate processing to all your sub-buses.
Since you start by attacking a mix from a zoomed-out perspective when mixing top-down, think of the bigger picture and how you can shape the mix as a whole using broad processing strokes. Perhaps you want the entire song to have a particularly “snappy” and “punchy” character; the SSL G-Master Buss Compressor has a notoriously tight and “forward” sound, so consider applying it to your stereo bus.
When it comes to stereo bus EQ, don’t bother with surgical processing. Use a wide bandwidth to apply boosts/cuts to your mix. If you’re familiar with video editing, color grading a video is quite similar to coloring a mix with an EQ. You can dig into your mix with your stereo bus EQ and sculpt the mix’s overall tone. The RS56 Passive EQ or PuigTec EQs would be perfect choices for such a scenario.
It’s okay to be aggressive with mixing decisions. You’ll sometimes find that moves you make at a track level are only affected by the plugins on your sub buses and stereo bus if you drive their level. When mixing bottom-up, a 9dB boost to the top end of your vocals may sound like too much, but when mixing top-down, that boost may trigger a saturator or another device on a bus that makes the boost feel just right. Just be wary of the fact that there’s processing being applied down the line.
You’ll likely notice that people who mix top-down aren’t afraid to push the limits of their tools. As you begin to adopt this aggressive mind-set, you’ll discover the real power of top down mixing; extreme tone-shaping possibilities.
Performing top-down mixing with transparent digital processing tools somewhat defeats the purpose of using this musical mixing technique. Analog-modeled plugins are the foundation of top-down mixing; they provide the color that many people are in pursuit of. Each piece of analog gear comes with its unique peculiarities because of its design, contributing to a more musical mix. For example, the CLA-2A uses variable release times dependent on the strength of the input signal. Hotter input signals will result in longer release times.
Mixing is often looked at as a very technical process, but non-linear analog processing helps make the strong argument that mixing is indeed an art form. Like there are different ways to paint a picture, there are different ways to sculpt a mix. Get familiar with your analog modeled plugins and the tones they provide; this will allow you to identify the sound you’re looking for and choose the appropriate tool for the job. The NLS Non-Linear Summer will provide you with authentic analog summing and console tone across your mix bus. If you know that you want to apply transparent compression across your drums, make use of the dbx 160 Compressor / Limiter’s clean tone.
Because you’re working with processing applied on your buses, gain staging is something that you need to take into consideration, even more than you would when mixing bottom up.
When you’re mixing your song, and everything is sounding great, you don’t need to think about gain staging too much, but what happens when you run into an issue? If you’re trying to apply a boost to your kick around 100-200 Hz to make it hit harder but the compressor on your drum bus is acting against the boost, you may need to reduce the level of all your drums or increase the threshold level of your drum bus compressor.
You don’t need every signal in your mix running at exactly -18dB between plugins, which is the recommended input level for many analog-modeled plugins. Sometimes, a higher input level will get you the results you’re looking for. Having said this, you should at least be aware that input level does matter, and in some cases, might be acting against the mixing goal you’re working towards. Having a basic understanding of gain staging will allow you to quickly troubleshoot many mix issues and finish your top-down mixes faster.
What type of processing are you meant to apply to your stereo bus? Anything is fair game, but I recommend shooting for a goal, like the sound of an analog console. You may want to emulate the sound of a specific analog console with your plugins, or potentially create the sound of a custom fantasy console by handpicking different analog-modeled plugins.
On my stereo bus, I like to use the RS56 Passive EQ, SSL G-Master Buss Compressor and the J37 Tape. The RS56 gives me the ability to make slight tweaks to the balance of my overall mix if necessary, the SSL G-Master Buss Compressor gives me “snappy” dynamics control and the J37 Tape is there to pull the mix together with some added color and saturation. For more of a controlled and gentle bus compression tone, maybe for an acoustic track, consider swapping out the SSL G-Master Buss Compressor for the V-Comp, which models the Neve 2254.
Bottom-up mixing is often very calculated and planned. Some people like this because they can set a goal, and if they’re familiar with their mixing tools, they can achieve their goal rather easily. The main problem with this type of mixing is that it can be so precise and calculated that the final mix ends up sounding sterile.
The main advantages that top-down mixing provides over bottom-up mixing are speed and efficiency, unique tone-shaping possibilities and reduced CPU load. The experimental and extreme nature of this type of workflow can lead you to creative places that you may not otherwise visit.
I recommend giving top-down mixing a try at least once; it’s a somewhat jarring experience that will reinvent the way you look at mixing. Even if you ultimately decide that traditional bottom-up mixing is your cup of tea, understanding that there are multiple ways to mix your music is an eye-opening experience.
Want more on choosing mix bus processing? Hear the shootout between mix bus compressors.
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