Sidechain Compression — What It Means in Music Production
Sidechain compression is a technique where a compressor on one signal is triggered by a separate signal. In electronic music, it is most commonly used to duck the bass or pads in time with the kick drum, creating the characteristic pumping groove that defines many genres of dance music.
Full Explanation
In standard compression, the compressor responds to the level of the signal it is processing. In sidechain compression, the compressor listens to an external "key" or "trigger" signal instead. When the trigger signal exceeds the threshold, the compressor attenuates the signal it is inserted on. This allows one element of a mix to create rhythmic space for another.
The most common sidechain setup in electronic music routes the kick drum to the sidechain input of a compressor on the bass channel. When the kick hits, the compressor ducks the bass, preventing the two from competing for the same low-frequency space and creating a rhythmic pumping effect. The attack and release settings determine how quickly the bass ducks and how quickly it recovers, which directly shapes the groove.
Beyond the classic kick-bass relationship, sidechain compression is used on pads, reverb returns, and even the entire mix bus (ducked by the kick) to create movement and space. Some producers use sidechain compression as a creative effect, with extreme settings creating obvious rhythmic pumping that becomes part of the musical identity of the track.
In Electronic Music
Sidechain compression is arguably the most important mixing technique in electronic dance music. In house and techno, the pumping effect created by sidechaining bass and pads to the kick is fundamental to the genre's groove. Typical settings: fast attack (0.1-1 ms), release timed to the BPM (50-150 ms depending on tempo), and 3-6 dB of gain reduction. For a more transparent approach, use sidechain with volume automation or a dedicated tool like LFOTool or Trackspacer instead of a traditional compressor.