From the course: Audio Foundations: Compression and Dynamic Processing

What are dynamics processors?

From the course: Audio Foundations: Compression and Dynamic Processing

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What are dynamics processors?

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In its simplest form, a dynamics processor is like an automatic volume control, turning the volume up when it's too soft or down when it's too loud. In the audio world, dynamics processors adjust the dynamic range of an audio signal by measuring a signal's amplitude over time, and setting up rules to react to any changes to that amplitude. The dynamics processors we will cover in this course are compressors, limiters, expander gates, de-essers, and transient shapers. Dynamics processors allow us to manipulate a signal's amplitude and dynamic range in a variety of different ways: sometimes reducing it, sometimes increasing it, and often doing both over a period of time. Before adjusting the amplitude, we must first specify the amplitude level at which the processor begins to react. This is called the threshold. Then we need to create a rule for what happens when that threshold is breached. For example, in a compressor, when the amplitude level of a signal crosses the threshold level, the signal above the threshold is compressed. All dynamics processors will work on this basic idea of an action, generally a specified signal level, creating a reaction, some form of dynamic change to the signal. All you are really doing is telling the processor what to look for and what to do when it happens. Here is a simple example that almost everyone can relate to. Let's say you are watching your favorite TV show and you have got the volume on your surround sound system all dialed in so you can hear your favorite actor's every word. Suddenly the commercials come on and you are blown out of your seat by the loudness. Of course, you instinctively reach for your remote control to turn the volume down, as to not wake up the entire neighborhood. As soon as you find that perfect level on your remote for the commercial break, inevitably your favorite program comes back on and you can't hear anything the actors are saying. Again, you instinctively reach for your remote to turn the volume back up to the pre-commercial level. In this common scenario, even if you didn't realize it, you are acting as a dynamics processor, a compressor to be specific. When that commercial break comes on, the relative difference between the level of your show and those loud commercials triggers a threshold in your brain that says "way too loud!" and you reach for your remote and turn it down, effectively compressing the dynamic range of the TV show relative to the louder commercials. Once the commercials end and the program comes back on, a threshold in your brain is triggered again saying "I can't hear what they just said!" and you return the volume back to its previous level. Now think about the TV example I just described and try to relate that to a real-world mixing dilemma. How about the words in a vocal track rising and falling above the level of the background music? We want to hear all those lyrics clearly, but we also don't want them to jump out of the mix too much. Dynamics processors to the rescue. A dynamics processor on your mixing console, in your rack of outboard gear, or in your DAW does the same exact thing that you do while you channel-surf on your couch, except that it's much faster and has a higher degree of accuracy. Once you get the hang of the basic concepts behind dynamic processing, these processors will quickly become some of the most useful tools in your studio, empowering you to create a tight, punchy, and focused mix.

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