Your kick drum is the anchor which keeps your mix grounded for the listener. As such, you want to have a clear and present kick in your mix. While you can and should use bass drum EQ to emphasize the lowest fundamental frequencies and boost the high mids to bring out more of the beater head, your kick can still get a bit smothered by the bass in your mix. This is why producers and mixing engineers reach for compression to sidechain bass to the kick drum.
Sidechaining your bass to your kick is a very simple yet effective concept. Whenever the kick plays, it trigger a compressor on the bass so that the bass temporarily ducks out of the way to leave the bottom end completely free for the kick.
This allows the transients of the kick to shine through unobstructed so the listener hears and feels it before the bass comes back in a few milliseconds later.
It’s incredibly simple to use yet effective in achieving a less cluttered, more purposeful low end.
How to Sidechain Bass to Kick
Let’s go through the simple steps to sidechain bass to the kick drum.
The first thing to do is drop a compressor with a sidechain feature on your bass track. Note this doesn’t have to be a bass guitar. You can use this on any track(s) in your mix which are low frequency heavy.
It’s a simple fact that when multiple tracks which are rich in the same frequencies play at the same time, they’re at odds with one another. One or both of those tracks is going to get a bit lost. In the low end, the kick always takes priority, hence the situational compression on other tracks.
You can begin with sidechaining whatever your bass track is, but you can replicate it to any other instruments which have their fundamental frequencies that low.
Set the Input Source
Once the compressor is on your bass track, select the sidechain input source and set it as your kick.
If you use multiple kick drums/samples to make up your overall kick, then you can select any one of the individual kick tracks or the overall kick bus if you have one set.
You just want to make sure that it’s set to whatever your main kick is.
For instance, if you have a secondary kick to supplement the main one which is only set to play during the chorus to give that section more energy, a sidechain on this kick wouldn’t compress the bass during the verse.
Set the Threshold
Like with any other compressor, we need to set the threshold. The difference with sidechain compression is that the threshold is linked to the level of the input source, in this case the kick.
We want to set this threshold so that it catches the quietest instance of that kick. If the kick was made from a live recording, there’s going to be a certain amount of dynamic range.
Finding the quietest “hit” on that kick in the whole mix ensures that every single kick will trigger that compressor.
Set the Ratio
The ratio determines how many dB of gain reduction the compressor will apply for every dB the threshold is exceeded.
I recently did a whole breakdown on explaining compressor ratio with an easy way to understand how the ratio works.
The only thing to truly understand is that a higher ratio means that it squeezes down on the signal you feed into the compressor harder, thus reducing the dynamic range more.
What Ratio to Use With Sidechain Compression
Determining what ratio to use with sidechain compression depends on knowing what you want.
A nice thing about sidechaining your bass to your kick is that the ratio will directly affect how much bass you want to duck.
If you completely want to get that bass out of the way for that kick transient, set a higher ratio at 10:1. Note that this can result in a pumping sound as you hear that compressor releasing the bass.
If you just want to drop the level of the bass a bit and go for a more natural and transparent effect, set it to 2:1 or 4:1.
Adjust this until you find the mix you want so that your bass is reduced enough that the kick is clearly heard and felt.
What Attack to Use With Sidechain Compression
The last thing to set is your attack and release times on that compressor.
Because the whole point of sidechaining bass to kick is to create room for the kick, we want that compressor to work immediately.
Therefore, drop the attack all the way as low and close to .000 ms as possible. This will instantly compress your bass whenever the kick triggers it.
What Release to Use With Sidechain Compression
You also want a short release, because the purpose of the sidechain compression is just to let the transients of that kick punch through untouched.
You also don’t want the release so short so that it comes on so fast that it still covers the kick’s transient.
Solo the kick and bass together and adjust the release so you hear a clear distinction between kick transient and that bass being released from its compression.
Sidechain Bass to Kick Tips
- Sidechaining your bass to your kick allows you to compressor or reduce the level of your bass when the kick hits.
- This is a great way to prioritize that cut and ensure it cuts through the mix unobstructed.
- To sidechain bass to kick, drop a compressor on the bass and set its input as the kick.
- Set the threshold low enough to pick up the quietest instance of the kick but high enough to not pick up ambient noise.
- Set the compressor ratio to reduce that bass more or less.
- A higher ratio will completely remove the bass when the kick plays.
- A lower ratio will drop its volume while sounding more transparent/natural.
- The attack should be set as low as possible to instantly compress the bass when the kick plays so the kick transient comes through.
- The release time should be adjust by ear. Trying soloing the kick and bass and adjust the release until you hear a distinction between the transient of the kick and the bass coming back on.