How to Sidechain in Logic Pro

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.

Set up a sidechain in Logic Pro

1. Add the stock Compressor to the track you want to duck (the bass or pad).
2. In the top-right of the Compressor’s window, open the Side Chain menu.
3. Choose the trigger track or its bus — most often the kick — as the sidechain source.
4. 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.)

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.

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.

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.