Sidechain compression is when one sound triggers a compressor on another, turning it down every time the first sound plays. The classic version is a kick drum ducking the bass or a pad so the kick punches through cleanly, and pushed harder that same trick is the pumping effect you hear all over house and EDM. Underneath it is just a normal compressor with its ear pointed at a different track.
Works in almost any DAW and on many compressor plugins, wherever a compressor lets you pick an external trigger. The idea is the technique, not one product.
Sidechain compression is a compressor that listens to one sound to decide how much to turn down another. A normal compressor watches the same signal it is turning down: the louder the vocal gets, the more the vocal is compressed. A sidechain compressor splits those two jobs apart, so the signal that triggers it and the signal it acts on are two different tracks.
The trigger goes into what most plugins call the sidechain or key input. The compressor still turns down the track it sits on, but now it opens and closes in time with whatever you feed that input instead of in time with itself. Point a kick drum at the sidechain input of a compressor on the bass, and the bass ducks whenever the kick plays, no matter what the bass is doing on its own.
The everyday example is exactly that kick and bass. Both live in the low end and fight for the same room, so a compressor goes on the bass and gets fed the kick. Every time the kick lands, the bass dips by a few dB and then recovers, so the kick punches through cleanly and the low end stops turning to mush. Nothing about the kick's own sound changes. It just clears itself a path.
A sidechain compressor is an ordinary compressor in every other way. Threshold, ratio, attack, release and the gain reduction meter all behave exactly as they do on any compressor. The single change is where it is listening: to another track instead of to itself. If those controls are new, our guide on what a compressor is and how to use it covers them from the start.
The pumping effect is the audible rise and fall you hear when a sustained sound is ducked hard on every kick and then swells back up before the next one. It is sidechain compression turned up past the point of being subtle, so the ducking stops being a quiet fix and becomes part of the groove.
In a lot of house and EDM, a pad, a chord stab or even the whole mix is sidechained to a steady four on the floor kick. On each beat the sound drops away, and in the gap before the next kick it breathes back in, so the track seems to inhale and exhale in time with the drums. That steady pump is the effect, and for many producers it is a sound they reach for on purpose rather than a byproduct they are trying to hide.
It started as a practical trick. Ducking the bass or the pad made room for the kick, and somewhere along the way people noticed that pushing it further sounded good in its own right. So you will hear it used both ways now: gently, so you feel the kick land without ever noticing the duck, and heavily, so the pumping itself is the point of the part.
The depth of the pump comes from the same controls as any compression. A lower threshold and a higher ratio duck the sound further on each hit, which reads as a stronger pump. A few dB of movement is enough to just make space; ten or more turns it into an obvious rhythmic effect. Start light, then push it until it does what the track needs.
Put a compressor on the track you want to duck, set its sidechain or key input to the trigger track, then set the threshold, ratio, attack and release so the sound ducks on each hit and recovers before the next one. That is the whole setup. The rest is in how you route the trigger and how you time the recovery.
The compressor goes on the target, the sound you want to get out of the way, which is usually the bass or the pad. It does not go on the kick. The kick is only the trigger, and its own sound stays untouched. A common beginner slip is to load the compressor onto the kick and wonder why nothing ducks.
Most compressors have a sidechain or key input with a little source menu. Open it and choose the kick. Some DAWs work the other way around, with no menu on the compressor: instead you leave the compressor set to listen externally and add a dedicated sidechain send on the kick track that feeds it. Either route reaches the same place, with the kick as the trigger and the bass as the thing that moves.
Lower the threshold until each kick pulls the target down, and raise the ratio for a firmer duck. Watch the gain reduction meter as you go. A few dB of movement is plenty for a clean fix that clears space without being heard; more than that gives you the obvious pumping sound on purpose.
A fast attack makes the duck land right on the kick, so the sound gets out of the way the instant the beat hits. The release sets how quickly it climbs back, and you want it to recover just before the next kick so the swell feels musical. Too fast and the effect turns choppy; too slow and the sound never fully comes back up between beats and just sits quiet.
| Control | What to do | Why |
|---|---|---|
| Sidechain input | Set it to the kick, or feed it a sidechain send from the kick | This is what makes it a sidechain and not a normal compressor |
| Threshold | Lower it until each trigger hit ducks the sound | Decides whether the compressor reacts to the trigger at all |
| Ratio | Higher for a firmer, more obvious duck | Sets how deep the ducking goes on each hit |
| Attack | Fast, so the duck lands right on the hit | A slow attack lets the sound through before it ducks |
| Release | Timed to recover just before the next hit | This is what locks the pump to the tempo |
Once it is moving, solo nothing and listen in the full mix, because the whole point is how the ducked part sits against the kick. Nudge the release by ear until the sound comes back up in the gap and never clashes with the next beat, and you are done.
Plenty. Once you can aim a compressor at a different signal, the kick and bass trick is only the most famous use of it. The same routing quietly solves a handful of other common jobs.
All of these are the same move you set up for the kick and bass, just pointed at a different pair of sounds. Learn the routing once and you have a general tool for making one thing step aside for another, whenever and however hard you want it to.
Sidechaining is a mixing step. It does nothing until you already have a sustained part to duck and a solid groove to duck it against, and writing those is the real work. The routing on this page takes a minute to learn; having a pad and a beat worth pointing it at is the job.
ARGISH is a self-playing pad and drone synth, and its slow evolving pad is exactly the kind of thing you sidechain to a kick so the whole track breathes. You set a mood and a key, and it composes and evolves a pad bed on its own, drifting and shifting without repeating, always in key. Route a kick at it in your DAW and the pumping effect on this page falls straight out. It runs as an Audio Unit, a VST3, an AAX for Pro Tools and a standalone app.
It also runs free in your browser, no install and no account, which is the fastest way to hear the kind of pad this trick is built for.
The sidechain itself lives on your compressor in any DAW, which is rather the point of writing it down.
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