Compression is an invaluable tool that can be applied to almost any sound. Therefore, here’s a friendly reminder about compression and the settings of attack and release on a compressor.
Most times compression is used to control dynamics and taming peaks to get a smooth, consistent signal. Other times compression is used to add punch, impact, proximity or for tonal control.
There are four settings on most compressors. The threshold controls the point at which compression begins. The ratio is the setting for how much compression is being applied. (A so called limiter is a compressor with a high ratio, e.g. inf:1, that will stop the signal at the set threshold.) Then there are attack and release settings. Attack sets how long it takes to reach maximum compression once the signal exceeds the threshold. And release sets how long it takes for compression to stop after the signal gets below the threshold. (Some compressors feature an auto release, which automatically adjusts the release time based on the incoming signal.)
Attack controls how much initial impact gets through.
A fast attack time shaves off the initial transient impact, and can make it sound more consistent and controlled. But when gone too far, the sound will lose vibrance and seem more further away.
A slow attack time is letting a lot of transient formation through. The initial impact will come through and the compressor will start to work after that. This can make it sound punchy, big and aggressive, but not very consistent dynamically.
For release time, again there are two options: fast and slow. In general, fast release can render a more aggressive, gritty sound – the initial sustain is sort of brought up, meaning more perceived loudness. But when the release time is too fast, it can sound exaggerated, distorted and bad, and there can also occur some pumping artifacts.
A slow release time will give more dynamic control, more smoothness, but also sound a bit distant. And if overdone with a slower release, the compressor will not release in time for the next hit to come through, and that can suck the life out of the initial impact and sound flat.
An effective way to stack compressors is to put the compressor with the fast attack time first and the compressor with the slow attack time second. The first compressor will smooth out those transients and make the initial hits more consistent, while the second compressor, fed by the dynamically controlled signal, will accentuate the initial hits.