The process of bringing together multiple channels of audio to create a blend of different sound sources is known as mixing. The essentials of mixing are balance and panning, which involve creating a harmonious relationship between each of the channels in regard to their volume levels and their position in the stereo field. However, as I’m sure you can imagine, there is a lot more to mixing than just that.
EQ and filtering allows for the sculpting of each sound’s frequency range, affecting its tone by either reducing or increasing the level of specific frequencies from the sub-sonic bass to ultra-sonic high frequencies and anywhere in-between. These changes are best done with respect to the mix as a whole, in order to prevent masking, muddy build-up, harshness and a host of other tonal issues that may need to be dealt with, as well as bringing certain elements to the foreground or setting others further back.
EQ can also be used to fix problems such as exaggerated resonances, as well as tonal variances, while dynamic EQ can be applied for automatic correction of audio which exhibits intermittent tonal variations throughout a recording.
Compression is most commonly used to control the dynamic range of a signal. Dynamic range is the difference in level between the loudest peaks and quietest troughs within the audio. A compressor is designed to react to the peaks, squashing them down by a specified amount, thereby reducing the dynamic range and allowing the overall level of the audio to be increased, without clipping.
That’s just one application of compression, which is far more versatile, and can also be used to exaggerate transients and add tonal variation as well as desirable distortion. When used in a side-chain, compression can also allow the signal of one channel to control the level of another, ducking it down when triggered, for instance enabling a kick drum to punch a hole through a dense mix, or for creating a signature pumping effect commonly found in dance music.
Compression is a remarkable and versatile tool, which also has a multitude of other applications, including de-essing, de-harshing and plosive control, all of which can be addressed through the use of different forms of multiband compression and many more uses besides.
A type of distortion, saturation is another key element of mixing, used to provide a certain flavour to a recording, with many varied types to choose from, including tape, valve and analogue circuitry, imparting a unique character on the audio, altering its tone as well as applying a different style of compression, which lends itself well to both gluing mix elements together and differentiating them from one another.
Reverb is another major part of mixing, offering a way to place mix elements in a variety of spaces and environments, from a small room to a concert hall, an oil tank to a football stadium. There are a ton of different types of reverb available, each suited for use on a range of sources, such spring reverbs, which sound great on guitars, plate reverbs, which often compliment vocals and impulse response algorithms that can emulate any real-world space imaginable.
Reverb is an excellent tool when used judiciously, for creating a believable acoustical environment for your musical elements to occupy, or for bringing into being unreal and unimaginable soundscapes, launching the listener on an otherworldly journey into sound.
Delay, or artificial echoe, is another primary tool in the mix engineers arsenal, which can also be used to create ambience in a similar way to reverb, but with less of the swamping clutter reverb can create, leaving more space between it’s repeated echoes.
Delay is perhaps even more versatile than reverb, as it can also be used to produce other effects, such as chorus phasing and flanging, which are simply very fast delays combined with subtle variations in timing and/or pitch, creating unique results that serve to thicken the audio signal in various ways that are pleasing to the ear and allow those elements to which they are applied to stand out from other aspects of a mix.
As previously mentioned, pitch correction is a common tool used to tighten up a wavering note. Alternatively, pitch correction can be used creatively, pushing it a lot harder to produce that iconic robotic style of vocal, brought to popular fame by artists such as Boys2Men, Cher and T-Pain, and is ubiquitous in modern R’n’B and UK hip-hop. Of course pitch correction isn’t limited to use on vocals, but can be used to great effect on live instruments, both subtly and in more extreme ways, opening up many creative possibilities.
This is an invaluable tool provided by all modern DAWs, which allows the recording of parameter adjustments over time, including anything from volume faders and pan knobs to effect sends and filter frequency. Automation provides a means of changing the sound of your audio in an almost limitless number of ways throughout the duration of your track, including synthesizer parameters, such as filter cut-off, LFO speed, reverb decay time or for adding perfect delay throws.
The possibilities are immense and, as such, automation is a game-changer as far as music production is concerned. Almost anything imaginable can be achieved through the proper use of automation, making it one of the most important techniques employed in modern mixing.
So, as you can probably tell, there’s a lot involved in the mixing process, from the purely technical to the highly creative, and it’s as much an essential part of music production as recording and editing, if not more so.
Of course, nothing is as important as the writing of the music in the first place. Music is, at its heart, a creative pursuit, and as I’ve already mentioned, mixing can be highly creative. In fact, once the technical aspects of mixing have been dealt with, creativity it the primary goal of any mix engineer.
It’s easy to become mired in the notion that every instrument in a mix needs to be audible throughout the track, but the key to a great mix is to follow the emotion, the groove and the feel of the music in order to take the listener on a sound journey.
The aim is to make the listener feel something, whether it’s sadness, joy or an urge to dance or nod their head, capturing that feeling in the music is what’s most important. If a certain instrument gets lost here or there, it doesn’t really matter, as long as they enjoy the experience in the most effective possible way.
Finally, it’s a common misconception that the last piece of the puzzle, when it comes to the music production process, known as mastering, is capable of fixing anything not addressed during mix-down. This is not the case. It is far better to fix any issues in the mix, so that the mastering engineer has as little to do as possible.