How to understand compression better – Effects Forum

The first goal of compression is to make quieter parts of a recording more audible.

Say you have recorded the phrase “I love trains”. And “trains” is quieter than the rest. Which makes it hard to hear it in a full song. A compressor would squeeze “I love” (ratio says how much, attack says how fast when it gets loud, release says how fast compressor lets go). Then you would compensate with the parameter gain/makeup, making the complete recording louder. And trains more audible.

The second goal is tonal shaping. Most analog compressors in a studio not only did the job if what I just described, they changed the sound of the recording because if their analog(u)e circuit. Similar to how an amp changes the sound of a clean guitar, just much more subtle. That’s why many plugins are modeled after analog(u)e compressors like the 1176 or the LA2A. You’d reach for these, because when compressing, they also make the sound warmer and fuller.

If you want to “learn” compression”, put a compressor onto a vocal track, turn the ratio all the way up and the threshold all the way down (make sure no AUTO function is enabled, because it might get really loud!), Attack and Release all the way to slowest. Then play your recording (never in solo, always with the track behind it) and slowly start turning Attack and then Release. Listen to how the vocal’s sound changes. Then change the ratio, 4:1 or 3:1 is a good place to start. Then adapt the threshold. If there is a meter that shows gain reduction, aim for no more than 5dB. Finally adapt makeup gain to what the compressor is taking away. So if your meter maxes out at 5dB, add 5dB.