Essential Processors/Processes For Mixing Music & Audio
Mixing music and audio is a technical skill that requires certain tools and processes to be done correctly. Professional mixers are called “engineers,” after all, and all engineering professions are governed by processes and defined tools (processors) for the job.
What are the essential processes and processors of mixing music/audio? Beyond the necessary tools of a mixer/workstation (hardware or software) and monitoring system (headphones or speakers), mixing engineers require gain staging, volume faders, pan pots, equalizers, compressor/limiters, distortion/saturation, time-based (delay/reverb) and modulation effects, and more.
In this article, we'll touch briefly on the necessary base components of a mixing rig. However, our main focus will be on the craft of mixing and the processes that make mixing possible.
I'll be prefacing our conversation with the bare necessities and basic philosophy of mixing. If you'd like to skip ahead directly to the essential processes, please do so by clicking this link.
The Bare Necessities Of A Mixing Engineer
There are a few base-level tools a mixing engineer needs to mix before we can even begin to talk about the essential processes.
First, a mixing engineer needs a mixer. This could be a physical mixer (analog or digital) like those seen in live venues and broadcast centres or mobile setups.
More commonly, today, this means a DAW (digital audio workstation). We also need a computer with adequate specifications to run a DAW properly.
The mixer/workstation is the central component that allows mixing to take place, so it's completely essential.
Second, a mixing engineer needs to be able to monitor the mix. This is generally a pair of studio-quality headphones and/or a pair of studio monitors (or multiple pairs of each).
In addition to the mixer/workstation and monitoring system, mixing engineers also require interfaces, cables and a working environment. These are beyond the scope of this article.
Mixing is also enhanced by acoustic treatment, studio furniture, external hard drives and more (also beyond the scope of this article).
Now that we've covered the basics, let's dive into the art of mixing and consider the essential processes that go into crafting a high-quality mix!
Visualizing The 3D Space Of Mixing
A great stereo audio/music mix has dimension. Just as we hear sound natural in 3D space, so too should a mix be in 3D space. This means there are the following three dimensions we should be concerned with in a mix:
With this dimensional framework, we can better comprehend the importance of the essential mixing processes.
The Depth Dimension Of Audio Mixes
The depth of a mix refers to the virtual separation of elements based on the perceived distance from the listener.
Depth is created mostly with volume differences and reverb times.
EQ in the high-end also has an effect on perceived distance/depth since high-frequency sound waves lose energy much faster than low-frequency sound waves. Therefore, cutting the high-end with EQ can push an element further back in the mix.
Compression also has an effect on depth due to its effect on transients. Fast-attack compression can attenuate transients, moving elements further away from the listener. Slow-attack compression can have the opposite effect, moving sources closer by accentuating the transient.
The Width Dimension Of Audio Mixes
The width of a stereo mix refers to the differences between the left and right channels and the perceived soundstage from left to right.
Width is created mostly with panning, especially with double-tracked/over-dubbed elements.
Any stereo effect can have an effect on the width of a mix, including many modulation effects and stereo delay.
The Height Dimension Of Audio Mixes
The height of a mix refers to the range of frequencies, from high to low, that are present in the mix. A tall mix will cover most of the audible range from 20 Hz to 20,000 Hz (sub-bass to air/brilliance), while a short mix will have a more limited frequency range.
While height is largely a matter of arrangement, EQ plays a major role in this dimension.
Mixing Essentials
Let's now focus our attention on the essential tools in a mix and how they affect each of the dimensions mentioned previously. I'll add links to more in-depth information as we go along!
The essentials for the art of mixing (excluding the necessary base-level equipment) include:
- Faders/Volume Control
- Panning
- Compression
- Limiting
- Equalization
- Distortion/Saturation
- Delay
- Reverb
- Modulation
- Sends
- Buses
Let's touch on each of these processes.
Faders/Volume Control
Channel faders control the volume of individual tracks and are necessary for balancing the mix.
A proper balance between the elements is the more critical aspect of a good mix.
Therefore, faders/volume control is an essential process for mixing.
Panning
Panning effectively places individual tracks (or buses) at an angle within the stereo field. Panning is the most basic method of creating width in a mix and provides separation between elements.
Compression
Compression is a super-powerful process, capable of many different tasks in producing a high-quality mix.
As the name suggests, compression is designed to compress the dynamic range of a signal (the difference between the “loudest” and “quietest” parts of the signal).
Compression is key for helping to maintain consistent levels of a mix's main elements (often the vocal). It's also invaluable in “gluing” a mix together, helping to relate all the elements together.
Compression is often used on individual tracks/elements, buses of tracks, mix buses and even during mastering.
Using serial compression (sending a signal through multiple compressors, one after another) is an important part of getting extra perceived loudness from a track. Note that this can be done by inserting a compressor on an individual track, another on that track's bus (if applicable), and another on the mix bus.
Beyond the basics of compression, this essential processor is the centrepiece of popular production techniques such as sidechain pumping and parallel compression.
Limiting
Limiting is like hard compression. Rather than reducing the dynamic range by reducing the level above a set threshold, a modern limiter will have an absolute cutoff level at which no additional signal level is possible.
Limiters help tremendously in preventing hard clipping in our DAWs and help increase the loudness of the mix and individual tracks within the mix.
Equalization
Equalization (EQ) is another super-important process in mixing.
EQ allows us to boost (increase the volume) or cut (decrease the volume) specific audio frequencies.
It plays a role in the height of the mix and also in the depth (particularly with the high-frequency bands).
EQ allows us to remove rumble, noise, resonance and harshness from individual tracks and the mix as a whole while also offering the ability to enhance the characteristic tone and timbre of the elements.
Furthermore, EQ helps in separating elements, providing yet another way to ensure each individual track is well-represented in the context of the greater mix.
Distortion/Saturation
Distortion is often given a bad wrap, especially in the digital age, where clipping distortion can quickly ruin the clarity and quality of an otherwise perfect audio signal.
However, distortion and saturation (the two are very similar) have been ubiquitous in many of the world's greatest mixes.
Distortion refers to any change in a waveform (typically excluding amplitude/gain). Any change in a waveform causes new frequencies in the resulting sound.
Saturation is a subtle form of distortion that adds pleasant-sounding harmonics.
Saturation and distortion are inherent in analog equipment, from tape to tubes, transistors to circuits, and even in cables (to some extent).
When people talk about the sterile, bright sound of digital, they're indirectly referencing the lack of saturation and distortion.
So, saturation is key for adding warmth to a mix. The added harmonics can also really bring out the sonic character of an element.
Additionally, distorting bass-heavy sources has the effect of enhancing the upper harmonics and providing a greater perceived level (our ears are much more sensitive to mid-range frequencies than bass and sub-bass frequencies).
Delay
As the name suggests, the delay effect delays a sound. It effectively copies a signal and plays it back after the original.
Delays happen naturally in acoustic spaces as reflections off surfaces. Therefore, delay can give a sense of dimension to a mix, particularly depth (the greater the delay time, the seemingly further the source).
Stereo delay or panned delay adds width to the mix as well.
This time-based effect is essential for adding dimension and realism to a mix.
Reverb
Reverb is another time-based effect responsible for mimicking the reverberation of an acoustic space. Some reverbs are designed with algorithms based on real rooms, while others are based on plate and spring technology.
Reverb is especially important for the depth dimension, with reverb times and early reflection times playing a major role in placing the source at a distance from the listener.
Another huge benefit of reverb is that it can be used to glue an entire mix together. Bus individual tracks together into a reverb and give the mix a sense that everything belongs in a defined space.
Modulation
Okay, maybe modulation effects aren't essential, but they do offer plenty of sonic excitement to a mix.
Modulation effects include:
Buses
A bus, in audio engineering, is a signal path used to combine multiple signals together and route them to a specific destination. Bus signal paths are physical in hardware or virtual in digital systems. Buses are often used for routing to subgroups, auxiliary tracks, and the outputs of a mixer.
This way, we can have individual tracks (with their own processes) outputted to a common bus, whereby they can all be processed together. This frees up resources and helps with the cohesiveness of the mix with common processing.
Subgroups
A subgroup is an additional track, beyond the individual audio tracks, that can have multiple tracks routed/bussed to it. Subgroups allow us to process the sum of specified tracks rather than having to process them each individually. This, in turn, reduces the number of processes/effects needed, simplifies our workflow, and helps “glue” the mix together.
It's common to see subgroups made from multiple tracks of the same instrument, like drum subgroups, guitar subgroups, vocal subgroups, etc.
Auxiliary Sends/Returns
A send is effectively a secondary path for a track to be sent to. This process maintains the original track (being sent to the mix bus) and adds an adjustable send amount to another track (also sent to the mix bus).
Sends allow for parallel processing and allow for easier wet/dry mixing. Additionally, multiple tracks can be routed to the same send/aux track, where a single effect insert can provide the same effect/process on all tracks.
Sends/auxes are excellent for master reverbs and delays to help establish a cohesive space for the mix to reside.
Recap On The Essentials
There's a lot to know about mixing. These are the essential processes within the mix, though there are plenty of other processes that go on in the grand scheme of music production.
That being said, learning the processes mentioned above will undoubtedly give you the skills to produce high-quality mixes!
Once again, the essentials are:
• Faders/Volume Control
• Panning
• Compression
• Limiting
• Equalization
• Distortion/Saturation
• Delay
• Reverb
• Modulation
• Sends
• Buses
Call To Action!
Consider each of the processors/processes mentioned in this article, and which would be the most important in your specific studio setup. Note that, with modern DAWs and plugins, we can get much of what we need “in the box”.
That said, it's good to have an idea or “wish list” of gear that could benefit your studio workflow.
Leave A Comment
Have any thoughts, questions or concerns? I invite you to add them to the comment section at the bottom of the page! I'd love to hear your insights and inquiries and will do my best to add to the conversation. Thanks!
