In Step 5 of this series I walked you through setting up processing and effects in your project template. Now that you have your structure, instrumentation, transitions, stems, basic processing & effects in place, it’s time to look at mix bus processing.
The vast majority of online tutorials and advice from professionals will tell you not to have any mix bus processing whatsoever, and with good reason. However, the real issue isn’t so black and white.
First of all, mix bus processing is a hotly debated topic. I have no intention of fuelling the fire further here, but it’s extremely important to know why it’s useful to have processing on your master bus, and how it can enhance your mix.
I’ll state up front that this is not a lesson in mastering. I repeat, this is NOT a mastering lesson. Mastering is an art form in and of itself. However, as I’ll explain, implementing some subtle mix bus processing can have great results and provide you with a better understanding of the mixing process as a whole.
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The mix bus processing controversy
As I’ve stated many times, music production is an extremely subjective process. What works for one person may not work for someone else. Of all the procedures throughout the mixing process, mix bus processing and mastering are perhaps the most controversial.
While there are no ‘rules’ per se, there are some key concepts that you can implement that will stand you in good stead for almost any mix. Understanding the basic techniques and knowing how, why and when to utilise them will take you a long way. The rest is almost totally subjective.
The difference is experience
The reason beginners and up-and-coming producers are advised to avoid this approach is because they often don’t have a good grasp on the technical subtleties in mixing, let alone mastering, and there is therefore a large space for error.
If, on the other hand, you take time to properly research and practice mixing, and gain a balanced understanding of the pros and cons of adding mix bus processing, you’re much more well-equipped to achieve success.
Thinking outside the box
In one sense, mixing without any master processing is akin to painting blindfolded. It’s difficult to predict how the final canvas will appear without having a big picture perspective. After all, if you’re going to apply master processing to your mix eventually, logically it just makes sense to get a sense of how it will sound as a final product.
By mixing into a mix bus chain, albeit even a very simple one, you’ll have a much clearer understanding of how your mix will come across as a completed track. The other big advantage to this approach, is that it exposes any potential issues, such as frequency imbalances and dynamic variations, before getting to the mastering stage.
I’m not alone
Don’t just take my word for it, though. Many seasoned producers and engineers also advocate this approach. Tomy Declerque, for example, sums up this methodology perfectly in an interview feature with Future Music:
Believe me, this can save a lot of time and a lot of back and forth, especially if you’re working with an external mastering engineer.
Graham Cochrane from Recording Revolution is also in agreement.
In summary, processing the mix as a whole has some significant benefits:
- Enables you to gain a more accurate understanding of how the track will translate at the mastering stage;
- Increases the overall cohesiveness of a track;
- Helps to ‘glue’ the track together (by processing all individual dynamics and frequencies as one body of sound).
Mix Bus Processing Fundamentals
All mix engineers have their own unique master chains and I encourage you to experiment and find out what works for you and your music.
However, having researched this topic a great deal over the years and applied many varying techniques myself, I have found that there are several core elements that form the key ingredients of any mix bus chain.
By the end of this lesson, you should be able to achieve the following:
- Identify 5 key plugins that you can add to your mix bus;
- Describe how these tools can enhance your music;
- Apply these plugins to your mix bus template.
[NOTE: Occasionally I’ll recommend third party plugins throughout these articles. I don’t have any affiliation with these manufacturers, so if I refer to a particular tool it’s simply because I’ve used it and I’ve had great experiences with it.]
With all of these approaches, the key is to be subtle and use each tool with caution.
You’ll notice that I specifically haven’t numbered each part of the chain. I prefer a particular order for my own processing but many people may disagree, and that’s absolutely normal!
So, while I have listed them in the order that I most commonly apply them in my own mixes, don’t treat this sequence as law. You should always look to experiment and trial different approaches to see if a particular variation creates a better result.
While a Gain plugin itself won’t have any impact on the actual sound of your mix, it can be a very handy tool in a project template. For example, if your mix is coming in a little hot, it gives you the ability to reduce the overall level without having to adjust individual faders.
Most engineers (including myself) recommend around 3-6 dB of headroom. You can therefore use a gain plugin to make any adjustments before going into your master chain.
You really can use any Gain plugin, just so long as it’s ‘transparent’ i.e. it doesn’t colour the input in any way. Most DAWs offer a stock Gain plugin (Logic’s can be found under the Utility dropdown). I also like FreeG from Sonalksis as the automation increments are less fine and more practical. As the name suggests, it’s free to download, but feel free to use whatever you prefer.
Many engineers prefer not to use EQ on their mix bus and there are a number of reasons to justify this.
One reason is that they believe that any frequency issues should be fixed within the tracks themselves, which is perfectly valid and certainly a logical approach. Another reason is that any additional processing on the mix bus introduces further aliasing issues that need to be accounted for – I don’t have the space to elaborate on this topic here but it’s an issue worth researching.
However, applying an EQ on your master bus can provide you with some distinct advantages. Foremost, applying EQ adjustments to the overall mix can provide a much more musical sound, rather than clinically cutting or boosting the EQ on individual tracks.
It’s also handy to have a more general tool at hand in certain scenarios, for example:
- Remove unneeded low-end frequency content with a hi-pass filter (around 20-40Hz depending on the material);
- Add a subtle low-end boost for warmth and punch (e.g. around 50Hz);
- Band cut the low-mids to reduce muddiness/wonkiness (e.g. around 200-500Hz) and increase relative clarity in the upper mids;
- Add some subtle ‘air’ (usually around 8kHz up) without introducing harshness.
As mentioned, mix bus processing is often described as a way of creating a more cohesive sounding track, that ‘glues’ all of the individual elements together. Compression, then, could be described as the ‘glue gun‘. By compressing a mix, you can add more punch, power and excitement to the dynamics, and therefore further engage the listener.
It’s important to apply mix bus compression with care. Here are some suggestions for enhancing your mix without squeezing the life out of it:
- Setting a slow attack (e.g. around 20-50ms) will allow transients to come through;
- A fast release will ensure that the compressor lets go of the music quickly and allows it to breathe;
- Apply a small ratio of around 2:1;
- Avoid too much gain reduction – aim for around 1-3 dB when setting the threshold.
You can use any stereo compressor on your mix bus, so don’t hesitate to grab your DAW’s stock compressor plugin. The key, as always, is understanding how to use it. Try applying some of the recommendations above – these subtle moves will add up in the overall mix bus chain.
If you have a little budget and want to try out something more exotic, I highly recommend the Waves SSL Master Bus Compressor, as it emulates the bus compression on the real SSL consoles. Many engineers swear by it.
Here I’m referring to really any kind of limiters or maximisers, with the Waves L2 and L3 plugins being famous examples. It’s important to apply some form of limiting to get a sense of how your final mix will be interpreted during the mastering process.
Generally, I would advise setting a ceiling of -0.3 dB. This is the more traditional level hailing from the days of CD masters, which would exhibit distortion once this level was exceeded.
However, if the destination of your mix is internet distribution on platforms such as SoundCloud and YouTube, you can push it to -0.2 dB. I wouldn’t recommend any further than this, as many platforms apply their own compression and limiting, and this therefore provides a little bit of wiggle room, just in case.
By applying this ‘brick wall’ limit on your mix, you’re able to experiment with the limiter’s threshold to drive the volume while applying gain reduction. Again at the mix bus stage, I don’t recommend pushing the gain reduction any further than around 2-4 dB, or you risk introducing low-end distortion and losing the attack of transients.
You can experiment with this by using something along the lines of the Waves L2 and cranking down the threshold. The L2 is an incredible tool and you can certainly cook it, however I really don’t advise it if you want to preserve the life and musicality in your mix.
Just as I recommend beginning your chain with some form of Gain adjustment tool, I also highly recommend bookending your chain with some form of metering. If you haven’t got into the habit of analysing your levels and imaging, now is the time to start. At the very least, you should be monitoring your output levels.
I don’t trust my ears after 40 minutes of intense listening as they have normally acclimatised to the track by this point. Therefore, it’s good to reference a factual and visual representation of the frequency spectrum and dynamics.
After all, if you’re going to add mix bus processing, you need to know what that mix bus processing is actually doing to your mix!
Depending on how in-depth you want to go, you could add your metering plugins before the limiter to monitor the levels before they hit the ‘brick wall’. I often place a meter before and after processing so that I get an accurate picture of what’s going in, as well as what’s coming out.
To begin with, try placing a metering plugin after the limiter to get an overall picture of the dynamics, frequency balance and stereo field.
On the bus
I hope this rundown on the key mix bus processing plugins was useful! Hopefully you should now have a good understanding of how these tools work, and are ready to begin applying them in your own projects to enhance your mixes.
As mentioned previously, there are few things to be aware of when processing the mix bus, and you need to be careful when making adjustments to the track as a whole.
I know this may disappoint some folks, but unfortunately there are no true presets that will work across every mix. Every piece of music presents a different set of problems requiring a different set of solutions. You need to listen to the track at hand, evaluate any issues and adjust accordingly.
Above all, if in doubt, keep it simple. You can totally transform a mix by adding all manner of crazy plugins to the master channel, and you can squash a track to within an inch of its life. But that doesn’t mean you should.
It’s no good throwing on an L2 limiter if you don’t understand dynamics processing, or creating some insane stereo width if you don’t know anything about phase relationship and mono translation.
How many compressors you place on your mix bus is totally up to you. As I always say, if it sounds good, then it is good. Just make sure that it sounds good!
It’s also very important to consider the order of your processing chain, too.
Classically, many producers argue whether EQ should come before compression, or vice versa. There is no right answer. Applying compression after EQ on a particular mix will create a particular sound.
Fundamentally, if it sounds good, it’s the correct approach.
Mix Bus Processing: Part 2
In the next post, I’ll explore some of the additional processing techniques that you may wish to add to your mix bus chain. However, you should only begin looking at these tools once you feel comfortable with the basics, so don’t rush into anything.
Get to grips with gain staging, EQ and compression before experimenting with anything else. These three skills alone will take you far.
Be sure not to miss it!