How to Sidechain EQ From Bass to Kick

As I recently covered with my bass guitar frequency chart, the bass and kick have a lot of overlap in their fundamental ranges. Typically the fundamental thickness of the kick which we feel just as importantly as hear peaks around 70Hz. This is right between the open A and D strings on the bass guitar, so we’re right in the heart of that bass, as well. I’ve talked about how to sidechain bass to kick to uniformly pull the volume of the bass down when the kick triggers. A more surgical alternative is to use sidechain EQ or specifically dynamic EQ to exclusively duck the bass in that fundamental frequency of the kick.

Let’s talk how to sidechain EQ from the bass to the kick to create space for the kick without disturbing the bass.

Sidechain EQ

Note that when I’m referring to sidechain EQ I’m referring to dynamically pulling a certainly frequency out of a track based on the behavior of another track.

This is not to be confused with the EQ feature on a sidechain compressor. In this case, the EQ feature allows you to only compress your target track based on the behavior of a specific frequency range of another track. You’d set that frequency range via the EQ on the sidechain compression, and the compressor would only use the audio within that range for its threshold.

But again, for our purposes we’re using dynamic EQ; a special type of EQ (or feature on an EQ) which pulls down an EQ band based on how loud that specific frequency range is at any one time.

As I mentioned when I compared dynamic EQ to multiband compression, dynamic EQ is great for surgical cuts when we don’t want to simply remove a frequency from a track altogether like a normal EQ.

Sidechain EQ on our bass is a good example and application of dynamic EQ to get it to work well with our kick, so let’s get into it.

Step 1 – Drop a Dynamic EQ on Your Bass

I’ll be using FabFilter’s Pro-Q for this example, but the process will be similar for any dynamic EQ.

Let’s drop the EQ on our bass track and create a bell type filter (see the 6 EQ filters).

This will work for sidechain EQing our bass to our kick regardless if its an organic bass guitar or synth bass.

As I covered in my FabFilter Pro-Q 3 review, my favorite EQ has the ability to make any frequency band dynamic. Simply right click the point and select “Make Dynamic”.

But where do we want to put this point?

Step 2 – Find the Peak of the Kick

Time to find the peak in that fundamental of the kick.

Drop a frequency analyzer on your kick. I just use another instance of Pro-Q because its spectrum grab feature shows and even labels where the prominent frequencies of your track exist.

In this image taken from my kick, we see the peak is roughly 64 Hz. It even shows a smaller overtone peak an octave up at 129Hz.

Of course if you use the sine wave kick drum trick to help thicken up and add to the fundamental of your kick, you likely already know the “peak” of your kick.

As I covered in that tutorial, you simply create a low frequency sine wave in that 50-80Hz region. You can even match the pitch of the wave to the key of your song for a little added cohesion.

A gate is added to that sine wave which opens when the kick triggers, so that sine wave plays with the kick, simulating the fundamental “meat” of a kick drum. This is useful for supplementing a thin or top heavy kick, or just adding to what you already have regardless.

So if your song is in the key of “C”, that C2 note would be at 65.41Hz.

Step 3 – Set Up Sidechain EQ

Now we just need to set the input and dial in the settings.

In Ableton Live, you simply pull up the track you want to act as the guide in the “Sidechain” section. Here I select my “Kick” track.

Make sure you tick the “External Sidechain Button” (shown in blue) below so that it uses the track you set as the sidechain to dictate the behavior which triggers that threshold.

At this point it’s just about dialing in the settings you want to attenuate the bass when the kick triggers.

I have the threshold set so anytime the kick plays, the dynamic EQ engages and pulls down at our selected frequency.

Make sure the Q is tight enough so that it’s primarily just pulling down the fundamental of the kick, or in our case roughly 64Hz.

It’s not a big cut; the gain reduction is set to pull on average 3dB out of that kick.

This should help give dominion to the kick in its most important range, but unlike using sidechain compression, the bass doesn’t have to uniformly duck out as often as most of the frequencies which aren’t competing with the kick are untouched.

You can still dial in a bit of sidechain compression alongside the sidechain EQ on the bass if you like to give the kick a little more space, but you can be more conservative with the settings this time.

Sidechain EQ Tips

• Sidechain EQ is a more surgical way to create the space you want between competing instruments like bass and kick.
• Using dynamic EQ, you can just pull out the frequencies the kick needs when it triggers instead of making a static volume cut as with sidechain compression.
• Find your kick’s fundamental, meaning its peak frequency under 100Hz, using a spectrum analyzer or simply using your EQ.
• Set a narrow bell at that frequency via a dynamic EQ on your bass and designate the kick as the input.
• Set up the dynamic, sidechain EQ to pull out 3-5dB when the kick triggers.
• Follow the sidechain EQ with a sidechain compressor if you need a little more space for the kick, admittedly with more conservative settings than you would’ve had to use without the sidechain EQ.