You might have heard musicians talk about compression as if it were some kind of dark art. To the uninitiated, the level of hoo-ha is baffling, because unlike delay or reverb, compression is not something you can easily hear as a listener.
But audio compression is something we hear on a daily basis – from the music we listen to on BandLab, to the movie screens, to your favourite TV shows. It’s a vital part of all things audio, and understanding how to use compression in your music will take your recording to the next level.
What is compression?
Compression is a process which reduces the amplitude range of an audio signal by reducing the peaks and bringing up the low levels.
To put it in simplest of terms, compression makes loud parts quieter, and soft parts louder.
Take a singer for example. During the climax of a song, he or she is likely to be singing with more intensity and volume than a quieter, slower part of a song. Compression makes sure you hear both the soft and loud parts clearly,
It’s commonly used on instruments as well. Bassists rely on compressors to even out their volume inconsistencies when slapping and popping. Guitarists use compressors to smooth out rhythm parts. Many even rely on compressors to achieve a specific tone – country guitarists employ heavy compression to nail that distinctive chicken picking twang and snap.
However, over-compressing a track can literally “squeeze” it to death. Dynamics are part and parcel of music, so too much compression removes the nuances that add complexity and texture to the song.
On BandLab, most of our effect presets on the Mix Editor include compression. For example, Punchy Rap has a healthy amount of compression added to give your vocals consistency and snap.
On the web, you can tweak the parameters of each preset, or build a chain of effects from scratch to make your own unique sound. To do this, choose a preset effect and click the fader button to open up your settings panel.
To start from scratch, make sure your Fx selection is set at None, then click the fader button. Click the “+ Add Effect” button and from the drop-down menu, choose Compressor.
Select Standard Compressor and you’ll find five knobs you can tweak:
- Attack Time refers to how quickly the compressor kicks in and reduces the volume of the audio. A slightly slower attack time (>10ms) sounds more natural and musical.
- Release is the opposite of attack. It refers to how long the compressor takes to disengage.
- Ratio determines how much the sound is compressed. The higher the ratio, the more compression is added. But how does the compressor know when it needs to compress?
- Squeeze refers to the threshold of the compressor. The compressor only starts to compress when it hits its threshold, so if you set Squeeze at -30dB, it means the compressor will not engage when the signal level is below that. But as soon as your signal peaks above -30dB, the compressor will kick in, compressing the signal based on the Ratio you set.
- Compressors reduce the level of the loudest signals. So after implementing compression, you usually end up with a quieter signal than the original. Makeup Gain recovers this lost level. Increase this to make the overall track louder.
Compression is an important and vital process of making a professional sounding track. The effect should be subtle, yet you feel its absence when you turn it off.
Give the effects on the Mix Editor a try, and as we dive into more of the many effects we have on BandLab.