Sidechain
Sidechain compression is a mixing technique where a compressor's gain reduction is triggered by an external signal. Most commonly used in EDM to make the kick drum duck the bass or synths, creating the pumping effect iconic to house and dance music.
In practice, sidechain compression routes the kick drum as a trigger signal into a compressor placed on the bass or a synth pad. Every time the kick hits, the compressor reduces the volume of the sidechained element, then releases quickly—producing the rhythmic pumping that drives the energy of EDM tracks.
Sidechain routing in FL Studio: assign the kick to a mixer channel, use its sidechain input on a Fruity Peak Controller or Parametric EQ 2 to modulate the volume of the bass channel. The attack and release settings determine how punchy or subtle the effect sounds.
Beyond the classic kick-to-bass ducking, sidechaining is also used to duck pads, reverb tails, and even entire stems to create space for the kick and keep mixes clean at high volume.