AudioCalcs
Sidechain Calculator — Attack & Release for BPM
Calculate attack and release times for sidechain compression based on BPM and ducking style.
How We Calculate This
Timing Calculation
Cycle time (ms) = (60,000 / BPM) × beat division
Release (ms) = Cycle × release percentage
Attack = small fixed value (≈0.1–8 ms)
The release is timed to the beat so the signal recovers smoothly before the next kick — at 120 BPM a quarter-note cycle is 60,000 ÷ 120 = 500 ms. The attack, by contrast, is a small fixed time chosen to clamp the kick transient; it does not grow with tempo or note length. Real-world sidechain attack sits around 0.1–10 ms — fast enough to duck on the transient without lengthening when you slow the track down.
Ducking Styles
Each ducking style sets a fixed attack and a release percentage of the cycle. Classic pump uses a fast 2 ms attack and a 70% release. Aggressive uses a near-instant 0.1 ms attack and an 85% release for deeper, longer ducking. Subtle uses a slower 8 ms attack so some transient passes through. The hold and release fill the rest of the cycle so the signal returns before the next trigger.
Frequently Asked Questions
Sidechain compression uses a trigger signal (typically a kick drum) to control a compressor on another track (typically bass, pads or a mix bus). When the kick hits, the compressor ducks the volume of the target track, creating space for the kick and producing the characteristic pumping effect heard in electronic dance music.
Classic pump works for most EDM, house and pop production. Aggressive ducking suits heavy dubstep or complextro. Subtle ducking is ideal for acoustic or vocal mixes where you want the bass to duck without an obvious effect. Breathing works well for ambient and progressive house. Listen and adjust to taste.
Volume shapers (LFO Tool, VolumeShaper, Kickstart) give more precise control over the ducking curve shape and are easier to sync to tempo. Compressors react dynamically to the actual trigger signal, which can feel more natural but is harder to fine-tune. Many producers use volume shapers for predictable pumping and compressors for subtle, reactive ducking.
For obvious pumping: ratio 4:1 to 8:1 with threshold around -25dB. For aggressive ducking: ratio 10:1 or higher with threshold around -20dB. For subtle ducking: ratio 2:1 to 3:1 with threshold around -30dB. The exact values depend on your source material levels.
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Last updated: March 2026
All calculations are estimates based on standard formulas. Always verify results for critical applications.