Love it or hate it, a distinctive characteristic of modern dance music is the rhythmic pumping and pulsing of instruments — most often a lead and/or bass line ducking in and out around a thumping bass drum. Its a sound we have the likes of Daft Punk to thank for, who used a cheap Alesis 3630 compressor’s sidechain function all over their Homework and Discovery albums to great effect in the late ’90s/early 2000s. Sidechaining is a method of triggering a change in a module (anything with a sidechain function) with an external audio signal – most commonly a compressor, ie. a bass drum signal triggering a change in a compressor on a bass line track.
Here’s how to achieve this with Ableton LIve, obviously the exact step by step method behind sidechaining differs slightly DAW to DAW, however the main steps should be quite similar.
Set yourself up with a basic beat and bass line, ensuring the bass line plays over the top of your kicks. Now drop a default compressor onto your bass line’s track. Clicking the arrow next to the title of the module open’s up the compressor’s sidechain functionality – click on the sidechain button and select your drum rack from the drop down menu below it. Another drop down menu appears below that – select your kick drum.
Ok, now press play. Still sound the same? That’s because we haven’t actually told the compressor to do anything with the bass drum’s signal yet. Click on the activity view of the compressor so we have visual feedback of this next step. Grab the threshold control and wind it all the way back to -inf dB. Now you should have some extreme ducking and be able to see how the signal is being affected. For most applications -inf dB is way too extreme, so wind that threshold back up until it sounds good to you.
There’s some other important settings we can tinker with too – Ratio, Attack and Release. Ratio controls the amount the bassline’s signal is reduced each time the drum hits, wind it up for a more extreme effect. Attack is how long the signal takes to duck, and Release how long it takes to recover once the bass drum’s hit has passed. Experimentation is key here, the results depends on tempo and your intended effect.
What else can we do?
A really great feature is that the kick drum – or whatever sound you’ve chosen to trigger the sidechain – doesn’t have to be activated to affect the bassline’s signal, it can be turned off so we have a pumping bassline without actually hearing the kickdrum. Pay attention next time you hear a cheesy EDM banger and you’ll hear a lot of this used in lead ups to drops. An audio source that’s kept silent but used for triggering is often called a dummy track.
Sidechained compressors can be really great when used on percussion too, give it a whirl on some busy hi-hats or cymbals and you’ll add a rhythmic drive you didn’t know your track was missing.
Of course, your compressor can be on anything. And your source doesn’t have to be the same length as the track it’s affecting, try experimenting with a busy 3 bar loop triggering a compressor on a 4 bar loop. If you’re feeling really wild, put a delay or beat repeat plug-in on your dummy track.
There’s mountains of possibilities here, both creative and useful for mixing – So get crackin!