Well hello there, fellow mixer! Today we’re gonna talk about something more subtle than the flashy delay/distortion/make-your-mix-10-miles-wide sort of things. Sidechain compression tends to be one of those little gems working under the scenes to subconsciously affect how a mix is heard. It’s usually not something that one can pick out (though there are obvious examples, especially in the dance music world) but it’s something that adds to the overall “pumpy” vibe of a mix.
So, let’s start easy. What is sidechain compression? Pretty freaking simple, in fact. A signal from track A is affecting a compressor that is placed on track B. That’s it. Load up a bus send on track A. Load up a compressor on track B. Select track A’s bus send as the “key input” on track B’s compressor.
Right now, we’re just talking about using the kick drum to affect the bass guitar, but there are plenty of other uses for sidechain compression. I’ll probably have future blog posts with me blabbing on about them. Be on the lookout for those.
There’s this super cool band named Fabl that I’ve worked with on a few albums. When they sent me this song, I knew I wanted a little “pump” in the kick/bass combo to give a bit of spice to the song. First take a listen to what we’re working with:
Great tune, eh? They really have a distinct sound and I love it.
Alright, so when mixing this, I did as I described earlier…popped a compressor on the bass synth track and then fed that with a send from the kick track. The attack and release are set to be pretty quick, knocking off a handful of db’s with each time the kick hits. What you get is a bit more interplay between the two instruments. It starts to feel like one instrument in unison rather than two separate ones.
Here’s the before and after. It’s subtle, but listen for how the bass pumps with each kick hit:
It’s not crazy sexy and over-the-top, but still super effective and adds to the mix. Not only does this add “pump” but it also helps the kick to cut through the mix as the bass temporarily “moves” out of the way on every kick. Pretty sneaky!