Compression Settings Calculator

A compressor needs four settings to behave predictably -- ratio, threshold, attack, and release -- and this calculator suggests reasonable starting values for each based on what you're compressing rather than making you guess. Source Type is the biggest driver: it sets a base compression Ratio (vocals and guitar default to a gentler 3:1, drums and bass to a firmer 4:1) and a starting Attack Time, because different sources need the compressor to react at different speeds -- drums are given a relatively slow 20 ms so the stick attack passes through before the compressor closes (a fast attack on drums clamps the transient and is how you remove punch rather than add it, and belongs on a peak limiter rather than a bus compressor), while bass gets a quicker 5 ms because its energy is in the sustain rather than the transient. Suggested Threshold is worked backward from the reduction you asked for: a compressor pulls an input level down by (level minus threshold) times (1 minus 1 over the ratio), so the threshold that produces exactly your Desired Gain Reduction on a peak sitting at 0 dBFS is minus that reduction divided by the ratio term. Raising Desired Gain Reduction therefore pushes the threshold DOWN, not up -- more reduction always means a lower threshold. Dynamic Range acts as a floor on that: if the threshold the arithmetic wants sits below your quietest passage, the compressor would be working on the entire signal rather than the peaks, so the calculator clamps the threshold to your Dynamic Range and reports the reduction that is actually achievable.

Release Time is tempo-synced rather than fixed in milliseconds: it is set as a fraction of one beat at your Song Tempo, so the compressor recovers in musical time instead of fighting the groove. Makeup Gain is exactly the gain reduction the suggested threshold produces on a 0 dBFS peak, so adding it back restores the peak to where it started. Desired Gain Reduction only steepens Suggested Ratio once it passes 10 dB -- below that, Ratio is set purely by Source Type, and only Suggested Threshold and Makeup Gain move with your reduction target. These are starting points for ears, not a replacement for them: real program material varies enough that the right setting is whatever sounds and reads correctly on a meter, not whatever a calculator suggests.