Snap compression

The classic way of adding punch to a sound is to draw for a compressor… but how exactly does one work? A compressor is an automatic volume control, with typical controls including Threshold, which sets the level that will trigger gain reduction; Ratio, which sets the proportion of reduction that will actually occur; and Attack and Release, which dictate how quickly the compressor reacts to the Threshold being breached.

After applying compression, Makeup Gain is used – whether automatically or manually – to match the volume level of the compressed and the original input signal, to help us see exactly what the compression is doing.

Compression was originally envisioned as a tool to level out particularly dynamic signals like vocals, bringing harsh shouts and subtle whispers into line with each other, for example. Clever engineers soon found that they could add punch by dialling in slow attack times, leaving the signal’s initial transient alone before the sustain portion is reduced in volume.

Applying makeup gain leaves us with a signal that’s still got the same average volume but a louder initial attack, and this adds punch. Whilst compression is generally great for this, it can also add colour or artefacts to the signal which may not be desirable in all cases.