What are dynamics?
Dynamics refer to the space between the loudest parts of a sound to the quietest part. The space between each part is typically referred to as the dynamic range. This definition can be applied to an entire song, or to a specific sound.
Dynamic sounds have a wide range between the quietest part of the sound and the loudest. For example, picture a snare hit. It has a very sudden peak that doesn’t last long. This means it has a wide dynamic range. A real flash in the pan. Compare that to an organ note. It stays the same level from the time it begins to the time the key is released. This means it's a less dynamic sound. Dynamics also exist within an entire performance. An obvious example is a singer singing quietly in the verse, and then belting it out in the chorus. The range between the quietest and loudest parts can often be as much as 20dB, which is a lot. especially when you're trying to balance it with a bunch of other elements. Like that very un-dynamic organ note. These dynamic swings can make it difficult to make everything fit together in a mix without imposing some kind of control on them. This is where audio compression comes in.
What is compression?
Audio compression is the process of taming the dynamic range. This is done with a compressor that sets specific limits on how much of a frequency is let through. They boost the quieter portions and lower the louder parts, providing a more consistent and balanced overall sound.
How much a compressor does is determined by the compressor's Ratio. Higher ratios affect the dynamic range more.
But why do it? Isn’t dynamic range a good thing?
It’s true, dynamics are good. But remember that you’re trying to get a consistent level in the mix. If something is too loud it’ll stand out and be awkward. If it’s too quiet it’ll get lost in the couch cushions of your mix. Finding a good balance of compression is an art that requires listening and learning.
Does this sound similar to adjusting the faders in your DAW? It should. That's basically what a compressor is doing, but automatically.
But be careful not to get carried away. Applying too much compression is a danger zone. Using only compression to try and balance levels in a mix will lead to a lifeless, punchless, and fatiguing mix. Yucky.
Use compression in conjunction with volume (gain) to get the best results.
