Music would be very boring indeed without variation, and that’s exactly what musical dynamics are all about: variations in loudness. Examples might be a quiet verse leading into a loud chorus, a synth line that gradually increases in volume, some notes within a pattern played louder to accent them, a singer belting out certain words for emphasis, and so on. There may be unintended variations too, such as a bassist or drummer unable to play each note or hit at a constant volume where required.
Fixing unintentional problems is one thing, but even deliberate accents and changes in volume will almost certainly need some control to fit the norms of what we as listeners expect to hear in a finished, cohesive mixdown, free of unexpected jolts in level and excessive variance. While mixing, you may also discover a build-up of low-level sounds such as background noise – too much of this can pile up, resulting in a cluttered, unclear mix.
So what can we do about all this? How can we get dynamics under control to create a solid, professional mix? Well, you could use volume automation to briefly turn down any overly loud notes, to cut out background noise, or to bring up the level where required, and so on… But that’d be a right old hassle. There’s got to be an easier way, right?
You’re in luck: help is at hand in the form of the many dynamics processors available to the modern producer, such as compressors, expanders, noise gates, transient shapers and limiters. These effects take the hard work out of managing levels, and in fact, they are more than mere functional tools, offering the possibility of imparting such qualities as character, ‘glue’, movement, punch and snap to your tracks when used wisely. For even greater precision, power and flexibility, there’s frequency-conscious compression, multiband dynamics and parallel processing.
Now the bad news: Dynamics processors are not especially intuitive, and many producers struggle to understand how they really work, which sometimes results in them doing more harm than good. What you need, then, is a solid grounding in the fundamentals of how these vital mix tools work, of the scientific-sounding terminology that goes along with them, and the tried-and-tested techniques and starting points that’ll allow you to use them with confidence. And – wouldn’t you know it? That’s exactly what we’ve prepared for you right here! Now fire up your DAW, open your plugin folder and get ready to Get Dynamic once and for all…
Introducing dynamics processors
When we talk about adding, reducing, changing or enhancing dynamics, we are, in essence, talking about manipulating volume levels. Dynamics exist at both a macro and micro scale, with the former concerning overall track levels and the latter the dynamics specific to a sound’s own amplitude envelope. The key tools we have for macro dynamics include broad-brush techniques such as song instrumentation, fader level rides and simply muting elements at certain times. At the micro scale, we can use these same techniques, but the vast majority of micro dynamics are handled by a set of tools called dynamics processors.
To understand what a dynamics processor is and how it works, let’s look again at how a sound’s levels change over time. Typically, it will have an attack stage, a sustained stage and a release. As an example, a piano note may have a sudden loud attack, preceded by a fast fade down to half the attack’s maximum level, then a much longer tail fading out to silence over time.
So, there are differences in level between a sound’s loudest and quietest parts, and we may want to change those differences, enhancing the quiet parts, lowering the louder parts or removing the quietest parts altogether.
Dynamics processors are level-dependent effects that allow us to do this in real time, based on the incoming signal level and parameters we set on them. Typical tools are compressors, limiters, gates and expanders, but we can also add to the list de-essers, duckers, ‘enhancers’, frequency-conscious compressors and multiband dynamics processors. There are also transient shapers that impose a user-adjustable envelope, triggered by the transient of a sound.
Making a good compression
So how do these devices work under the hood? Before we talk tech, imagine this simple – if slightly far-fetched – scenario: inside your compressor is a tiny imp with its hand on a single, plain-old volume knob that can be used to adjust the outgoing signal’s level. The imp’s job is to constantly monitor the level of the incoming audio signal, and if it exceeds a certain level – called the threshold – to spring into action, turning down the volume knob by a proportional amount, known as the ratio. The more the input signal exceeds the threshold, the more the imp must reduce the output volume.
There’s more, though, as the poor imp has been given exact instructions as to the amount of time it should take to turn the volume knob down when this happens, whether it’s a lightning-fast fraction of a millisecond, or a leisurely half a second… or something in between. This is known as the attack time. That’s not all, either: what goes up must come down, and once the incoming signal level backs off, our beleaguered imp has to bring the volume level back up accordingly, again following a precise instruction as to how long it should take, known as the release time.
That is, more or less, how a compressor works, though in the real world you’d have to replace the imp with a chunk of code to continuously track the input level (known as the ‘detector’), calculate how the output level should be modified (the ‘gain calculator‘), and then control
