The basics: manual compression
Sometimes the simplest approach is best
Electronic compressors as we know them only became widely used in the 60s. That doesn’t mean people weren’t using compression before then, though, they were just doing it ‘by hand’…
In the broadest possible sense, compression is about managing dynamic range. Dynamic range is the difference between the loudest and softest sounds in a song or performance. Voice, bass guitar and percussion all have a naturally wide dynamic range, whereas solo flute or sustained string chords tend to be much less ‘peaky’, that is, more consistent and with less dynamic range.
In any mix there will be an ideal dynamic range for each instrument – enough variety to keep interest and emotion, but controlled enough to remain audible, without getting lost or overpowering other elements.
Microphone technique
The very simplest and most direct way to manage dynamic range is at the source. A great example of this for singers is to use what is broadly described as ‘microphone technique’.
You’ll often notice a great live singer pulling the mic away for the loudest notes and bringing it close in for quiet, intimate moments. You can achieve the same thing by asking a singer to move in and out from the mic in the studio.
This strategy has pros and cons. On the plus side it’s immediate, effective and cheap. On the other hand it takes skill and practice to get right. Many singers overdo it and removing the effect can end up being more time-consuming than using our second manual compression option…
Riding the fader
In a nutshell, you can turn anything that is too loud down and anything that is too quiet up.
Just like microphone technique, there are pros and cons to this approach. As with microphone technique it’s free, and it sounds very natural. The mixer chooses the ideal level for every phrase, and so long as the level doesn’t change, the part sounds entirely natural. On the downside, this is a very time-consuming method. Even with modern computer-based automation technology, it can take many runs through a track to get everything just right. Also, like the mic technique, it doesn’t have that distinctive compressed sound that a lot of genres require. More on that later.
It’s worth experimenting with though. We’ve done a few mixes using only minimal compression, with everything else being done by hand; the results can be superb. In particular, riding a fader into a compressor can get great results – you can get even more control and the compressor doesn’t have to work as hard.
Often there are times when manual compression isn’t enough, though, or is simply too time-consuming. For example, if a vocal can be balanced line by line, that’s great, but the human voice is one of the most dynamic sound sources you can record and often we need much finer control. In such cases, it’s time to break out a compressor.