I have recently been spending time in analogue and digital studios working on post production for a rather unusual animation. This is only my second endeavour in live studio recording, with the first being a rock band a few years ago. Although the projects are completely different, many of the same principles apply and compression is defiantly one of them.
Compression is the process of reducing the dynamic range of an audio signal, by lowering the loudest parts of signal and boosting the quietest. This is usually done for correctional reasons, but in some cases experimental. Although compression is almost necessary in most mixdowns, the best way to moderate its use to make sure recoding techniques are executed to a high standard. Sometimes this isn’t always accomplishable as not everyone has unlimited studio use, expensive mics and artists with lengthy studio experience, so developing a understanding for compression practises can define a ‘tight’ track from a ‘noisy’ one.
So let’s look at the five parameters of compression:
Threshold- This sets a level for compression to take place, hence if I set a threshold to 10 dB, any signal passing the 10 dB threshold would be compressed, leaving anything underneath the threshold untouched.
Ratio: The amount of compression that takes place at the threshold, I.E. 4:1: every 4 dB of volume above the threshold would be compressed down to 1 dB.
Attack- Simply how quickly (milliseconds) the compressor starts to work, great for adding ‘punch’ to a track.
Release- how long (ms) it takes for the compression to stop once it dips below the threshold. This is useful when adding sustain to a track.
Output: sets an overall output level (dB) from the compressor, this is executes once the compression as been completed, it allows for the reduced volume to be ‘added’ to the level of choice, this is known as make-up gain.
Here is a lovely example of dynamic compression being used simply on a track:
youtube video by wada1942, ‘a better way to use compression’
Remember compression is a subjective metric, which has been transformed over industrial mass production of music, this has caused great debate between music producers over the last 20 years, and I look forward to sharing my interests on ‘sound wars’ soon.