Here is how to sidechain in Logic Pro: put a Compressor on the track you want to duck, set its sidechain input to the trigger track (usually the kick), and dial in the threshold and attack/release so the trigger pushes the level down rhythmically. It is the classic move for making a kick and bass share space, and for that pumping pad effect.
This guide assumes a Logic Pro project with at least two tracks — say a kick and a bass, or a kick and a synth pad.
What sidechain compression does
Normally a compressor reacts to the signal passing through it. Sidechaining tells it to react to a different signal instead. So a compressor on your bass can be triggered by the kick, ducking the bass each time the kick hits. This carves out room so the low end stays clean and punchy. The same idea creates the rhythmic “breathing” pump on pads and synths in dance music. If you want the underlying theory before diving into Logic, read what sidechain compression is first.
Set up a sidechain in Logic Pro
- Add the stock Compressor to the track you want to duck (the bass or pad).
- In the top-right of the Compressor’s window, open the Side Chain menu.
- Choose the trigger track or its bus — most often the kick — as the sidechain source.
- Lower the threshold until the kick visibly pulls the level down on the gain-reduction meter.
You do not have to physically reroute audio in Logic to sidechain the Compressor — selecting the source in the Side Chain menu is enough. (For other plug-ins or effects that need a true routed signal, you would send the trigger to a bus and select that bus.) If buses are new to you, see what a bus is in mixing.
Dial in attack and release
The feel lives in the timing controls:
- Attack: faster attack clamps down immediately for a tight duck; slightly slower lets the kick transient through first.
- Release: set this so the level recovers in time with the groove — too fast sounds jittery, too slow and the bass never comes back before the next hit.
- Ratio and threshold: together set how much ducking you get. Watch the gain-reduction meter and listen.
For the underlying mechanics of these controls, see EQ and compression fundamentals, and if attack, release and ratio still feel abstract, our guide on how to use a compressor walks through each one.
Choosing the right trigger source
The trigger is whatever you want to control the ducking. Most of the time that is the kick, but the choice matters more than it first appears. If your kick lives on a single audio or instrument track, point the Side Chain menu straight at it. If the kick is layered across several tracks, route those layers to a dedicated bus first and select that bus, so every layer drives the duck consistently.
One thing worth knowing: the Compressor listens to whatever the trigger track is actually sending, including its own effects. If you have a reverb or a long tail on the kick, that tail can keep the ducking open longer than you expect. For the tightest, most predictable trigger, sidechain from a clean, dry kick — or duplicate the kick to a muted “trigger” track that exists only to drive the compressor, free of reverb and routed nowhere audible.
Subtle ducking vs obvious pumping
There are two goals. For a clean mix, use gentle ducking you can barely hear — just enough that bass and kick stop fighting. For an effect, push the threshold and depth so the pump is obvious and musical. Both start from the same setup; only the amount changes. If you mix electronic music across DAWs, the concept is identical to sidechaining in FL Studio and sidechaining in Ableton Live — only the menus differ.
Where sidechaining helps in a mix
Beyond kick-and-bass, try sidechaining a reverb or delay return to the lead vocal so effects duck while the singer is loud and bloom in the gaps. Route the return correctly using sends and returns in a DAW. For more Logic and mixing tutorials, browse the mixing and mastering hub.
A few other places it earns its keep: ducking a busy synth pad or pluck against the lead so the melody always sits on top; tucking a sustained guitar or string layer under a vocal phrase; and controlling a sub-heavy 808 against the kick so the two low-end sources do not pile up and trip your limiter. Sidechaining is one of the most reliable ways to mix kick and bass together. The pattern is always the same — find the two elements competing for the same space, and let the more important one duck the other.
Common sidechain mistakes to avoid
A handful of issues account for most “it sounds wrong” sidechain problems:
- Too much depth. If the ducked track audibly drops out and slams back, you have gone too far. Pull the threshold up until the movement supports the groove rather than distracting from it (unless an obvious pump is the goal).
- Release fighting the tempo. A release that does not match the song’s pace makes the bass feel like it is gasping. Adjust it against the beat, not in isolation.
- Sidechaining the whole bass when only the lows clash. Often it is just the sub frequencies fighting the kick. Ducking the entire bass can thin it out; consider only treating the low end where the conflict actually lives.
- Forgetting to check in context. A duck that sounds perfect on the bass solo can disappear under a full arrangement. Always confirm with the whole mix playing.
Frequently asked questions
Do I need a separate bus to sidechain in Logic Pro?
For the stock Compressor, no — just pick the trigger track in the plug-in’s Side Chain menu. Some effects that need an actual routed signal do require sending the trigger to a bus and selecting that bus as the source.
Why isn’t my sidechain working?
Check three things: the Side Chain source is set to the correct trigger track, the threshold is low enough to produce gain reduction when the trigger plays, and the trigger track is actually outputting audio. The gain-reduction meter should move with the trigger.
What’s the best release time for sidechain compression?
Match it to the groove so the ducked track recovers just before the next trigger hit. On a four-on-the-floor beat that is usually a medium release. Trust your ears and the gain-reduction meter rather than a fixed number.
Can I sidechain to a MIDI or audio kick I don’t want to hear?
Yes. Create a duplicate kick track to act purely as a trigger, mute its audible output or route it somewhere silent, and select it as the Side Chain source. The Compressor still “hears” it for triggering even though it is not in the mix, which gives you a clean, dedicated trigger you can shape independently.
