Sidechain compression is a technique where one track’s volume is automatically reduced by the level of a different track. Instead of a compressor reacting to the audio passing through it, it listens to an external signal — the “sidechain” — and ducks accordingly. The classic example is making a bass line dip every time the kick drum hits.
It’s one of the most useful tools in modern mixing and a defining sound in dance, pop and hip-hop. Here’s exactly how it works and how to set it up.
How sidechain compression actually works
A normal compressor turns down a signal when that same signal gets too loud. With sidechain compression, you feed the compressor a second input to control the gain reduction. The compressor still processes the original track, but it decides how much to duck based on the sidechain input.
So when you put a compressor on the bass and route the kick drum into its sidechain, the bass gets turned down every time the kick plays. The moment the kick stops, the bass returns to full level. The result is that the kick and bass take turns occupying the low end instead of fighting for it — and if that low-end clash is your main problem, our guide to mixing kick and bass together covers the other tricks that pair well with sidechaining.
It helps to picture the compressor as having two ears. One ear hears the track it’s actually processing — the bass — and that audio is never altered on its way to the sidechain “listener”. The other ear hears only the trigger you send it. The detection circuit watches the trigger and applies gain reduction to the bass, but the bass itself never decides when ducking happens. That separation is the whole point: the loudness of one part of your mix controls the loudness of another.
If you’re still building your foundation, our EQ and compression fundamentals guide covers how standard compression behaves first — it makes the sidechain version click faster.
Why producers use sidechain compression
- Kick and bass separation: the most common use. Ducking the bass under the kick keeps the low end tight and stops it sounding muddy.
- The “pumping” effect: in EDM and pop, heavy sidechaining of pads, synths or even the whole mix to the kick creates a rhythmic breathing pulse.
- Vocal clarity: ducking a busy instrumental or reverb tail whenever the lead vocal sings keeps the words upfront without riding faders.
- Controlling reverb and delay: sidechaining an effect return to the dry signal keeps the effect out of the way during notes and lets it bloom in the gaps.
How to set up sidechain compression
The exact steps vary slightly by DAW, but the concept is identical everywhere. We have dedicated walkthroughs for the most common setups, including sidechaining in Ableton Live, in FL Studio and in Logic Pro if you want screenshots for your own software.
- Put a compressor that supports sidechain/external input on the track you want to duck — for example, the bass.
- In the compressor’s sidechain section, select the trigger track as the external input — for example, the kick.
- Set a fast attack so the compressor reacts the instant the kick hits.
- Set the release to match the tempo — long enough to hear the dip, short enough that the bass recovers before the next kick.
- Lower the threshold until you get the amount of ducking you want, usually a few dB for subtle separation or much more for an obvious pump.
Getting clean levels into the compressor matters here too. If your tracks are inconsistent, review gain staging first so the sidechain triggers predictably.
Dialling in attack, release and ratio
The three controls that shape the feel of a sidechain are attack, release and ratio, and small changes make a big difference. Attack sets how quickly the duck begins once the trigger fires. For tight kick-and-bass work you want a fast attack so the bass gets out of the way immediately; slow it down deliberately only if you want the very front of the bass note to poke through before it dips.
Release controls how the level recovers, and this is where the technique either grooves or stumbles. Tie the release loosely to your tempo: a faster track wants a shorter release so the bass is back up before the next hit, while a slower track can breathe with a longer one. If the recovery sounds jerky, it’s usually the release fighting the rhythm — nudge it until the return feels smooth and musical rather than abrupt.
Ratio decides how hard the duck pushes. A gentle ratio gives you transparent separation that you feel more than hear, while a high ratio produces the dramatic pump that drives a lot of electronic music. Set ratio and threshold together: a high ratio with a deep threshold pulls the level right down, whereas a moderate ratio with a shallow threshold just nudges things apart.
Subtle vs obvious sidechaining
There are two ways to use the technique. Subtle sidechaining is a mixing tool — a few dB of ducking that you feel more than hear, used to carve space. Obvious sidechaining is a creative effect — deep, rhythmic pumping that becomes part of the production. Decide which you’re after before you set the controls, because they call for very different threshold and ratio settings.
Sidechaining without a kick: using a ghost track
If you want the pumping effect but your kick isn’t consistent (or you want pumping in a section with no kick), create a silent MIDI track with a four-on-the-floor pattern triggering a click or short sample, and use that as your sidechain trigger. Many producers also use dedicated volume-shaper plugins that draw the ducking curve directly, which gives tighter control than a compressor.
Common mistakes
- Release too long: the bass never fully recovers, leaving an audible gap or weak low end.
- Attack too slow: the duck happens late and you hear a click of the kick and bass overlapping.
- Overdoing it: heavy pumping on everything quickly becomes tiring. Use it where it serves the song.
- Triggering off the wrong source: if the trigger track has inconsistent levels, the ducking becomes uneven. Feed the compressor a clean, steady trigger — or a dedicated ghost track — so every hit behaves the same.
- Forgetting to check in mono and at low volume: sidechaining that sounds perfect on loud studio monitors can feel lifeless on a phone speaker. Check the balance the way most listeners will actually hear it.
Once you’re comfortable, sidechaining fits naturally into a broader workflow — see our beginner’s guide to mixing your first song and the full mixing and mastering hub for where it fits in the chain.
Frequently asked questions
Is sidechain compression only for electronic music?
No. While the pumping effect is associated with EDM, subtle sidechaining of bass to kick is useful in almost every genre, including rock, pop, hip-hop and even acoustic mixes where the low end needs tidying.
Do I need a special plugin for sidechain compression?
Most modern DAWs include a stock compressor with an external sidechain input, so you usually don’t need anything extra. Dedicated volume-shaper plugins offer more precise control, but they’re optional.
What’s the difference between sidechain compression and ducking?
They’re effectively the same thing. “Ducking” is just a common term for the result of sidechain compression — one signal getting turned down whenever another is present.
Should I sidechain before or after EQ in the chain?
It depends on what you’re trying to fix. Placing EQ before the sidechain compressor lets you clean up the trigger or the ducked track first, which often makes the ducking more predictable. If you only want the compressor reacting to a specific part of the trigger, such as the kick’s low thump, many compressors let you filter the sidechain signal internally so it responds to those frequencies rather than the full track.
