Put a compressor on the part you want to duck, switch it to an external sidechain, and route the kick to that input. Every kick hit then turns the part down. Lower the threshold until it ducks on each kick, use a fast attack, and set the release so the level is back up before the next kick.

How sidechain compression works

A compressor normally listens to the sound it's turning down. With an external sidechain, it listens to another track instead. Key it from the kick and the bass, pad or reverb return drops on every kick hit, then comes back up.

Kick track routed to SC input SC HPF filters sub from detector Detector Peak or RMS Gain reduction Threshold, Ratio, Knee Bass bus compressed ducks on each kick hit Diagram by Remi Blaze · remiblaze.com Kick track routed to SC input SC HPF filters sub from detector Detector Peak or RMS Gain reduction Threshold, Ratio, Knee Bass bus compressed ducks on each kick hit Diagram by Remi Blaze · remiblaze.com
The kick only drives the detector. You never hear it through the compressor.

Set it up with Furnix

Put Furnix on the part you want to duck, turn on EXT SC, and route the kick to its sidechain input in your DAW. Then:

  • Threshold and Ratio set the depth. Lower Thresh until the gain reduction meter moves on every kick. A higher Ratio ducks harder.
  • Attack as fast as it goes without clicking, so the duck starts with the kick.
  • Release sets how the part swells back. Turn on Grid Sync to lock the release to a note value, such as 1/8 or 1/4, so the pump moves with the tempo.
  • SC HPF filters the sub out of the trigger, so the detector reacts to the kick's hit, not its long low tail.
Tip Turn on SC EAR to hear what the detector hears while you set SC HPF.

Set the release to the groove

The release decides the feel. A short release ducks only the kick's hit and keeps the part steady. A longer one gives the audible pump you hear in a lot of house music. Too long and the part never recovers before the next kick, so it just sounds quieter.

Listen with the whole groove playing and adjust until the swell lands where you want it in the beat.

Clicks and lookahead

If the duck clicks, the compressor is grabbing the part a hair late. Look (lookahead, 0 to 5 ms) lets Furnix see the kick coming and catch it cleanly. Furnix reports the latency to your DAW, which compensates for it.

Or use a volume shaper

Pumpit draws the duck as a curve instead of compressing. Set Trigger mode to Sidechain to follow the kick, or Auto to duck in time with your project with no routing at all. Turn on MULTI to duck only the low end.

The Pumpit manual FAQ covers when to choose Auto or Sidechain, and the plugin workflow walkthrough shows a full sidechain setup in a finished track.

How do I sidechain a bass to the kick with Furnix?

  1. Insert Furnix on the bass. Put Furnix on the bass, or on the part you want to duck.
  2. Route the kick. Turn on EXT SC and route the kick to Furnix's sidechain input in your DAW.
  3. Filter the trigger. Raise SC HPF so the sub of the kick does not drive the detector.
  4. Set the depth. Lower Thresh until the gain reduction meter moves on every kick, and raise Ratio for a deeper duck.
  5. Set the timing. Use a fast attack, then set the release, or Grid Sync, so the bass is back up before the next kick.

Frequently Asked Questions

Anything that fights the kick for space: the bass first, then pads, chords and reverb returns. Duck each one only as much as it needs.

Both work. A compressor follows how hard the kick hits. A volume shaper draws the same curve every time and can run without any routing. Pick by the feel you want.

The duck starts a little after the kick. Use a faster attack, add lookahead, or both.

Yes. Pumpit's Auto trigger mode ducks in time with your project, so it needs no sidechain route.

Plugins in this post

This tip uses Furnix 1.1.0 and Pumpit 1.0.1. Some steps may differ, or not apply, if you're on a different version. Tried this workflow, or got stuck along the way? We'd love to hear from you: contact us.

More on dynamics

All dynamics posts →