Kick and Bass: The Sidechain Moves We Use to Keep Both Loud

Every record I finish comes back to the same argument: the kick and the bass both want the same octave, and only one of them can win at any given millisecond. On our own releases we usually solve it with a sidechain, but the way West Coast electro, UK techno, and IDM records duck the bass is not one technique. It is at least five, and they sound different enough that picking the wrong one is the difference between a track that pumps and a track that flams.

Here is what I actually reach for, in the order I tend to try it.

Start with arrangement, not the compressor

If the kick and bass are landing on the exact same note at the exact same time for the whole bar, no sidechain setting will save you. The cleanest low end I have mixed came from basslines that simply moved out of the way. Kick on the downbeat, bass answers on the off, or bass holds a note the kick never plays. That is composition doing the work, and it is free.

When that is not possible, the next cheapest move is frequency separation. Put the kick fundamental in one narrow band and let the bass live in a slightly different one. If they truly overlap, that is when you duck. The grounding for this is old and boring: one kick and one bass in the low range, ideally mostly present in different bands, and sidechain if they share the same frequencies. Layering two basses to fix a thin one is almost always the wrong instinct. It makes some notes loud and others quiet, and it eats your headroom for nothing.

The basic duck: attack, release, ratio

The standard sidechain compression move is the one most people mean. The kick hits, a compressor on the bass track pulls it down, and it climbs back before the next kick. The settings do most of the character work.

Attack: fast, around 1 to 5 ms, so the bass clears before the kick transient lands. Push it too fast and you get an audible click where the level jumps. Backing off to 5 to 10 ms usually smooths that without losing the duck.
Release: the part everyone gets wrong. The bass needs to recover before the next kick, or it never actually comes back and you just have a quiet bassline. For mid-tempo stuff, 100 to 200 ms is a decent starting point. Faster tracks want 50 to 100 ms. Auto-release on modern compressors is usually good enough that I stop calculating and just listen.
Ratio and threshold: this is your intensity dial. 2 to 4 dB of gain reduction is separation you feel but never hear. 6 to 10 dB or more is the pumping that becomes part of the groove. For techno and electro, obvious pumping is the point. For anything with a live feel, keep it under 4 dB and nobody will notice the duck, only that the low end is clear.

Threshold placement matters more than people admit. Set it low and ghost kicks and light hits trigger ducking. Set it high and only the loud ones do. On a track with programmed dynamics, that difference changes the whole rhythmic feel of the bass.

When the source itself is the problem

Audio-triggered sidechain detects whatever the kick track is doing, including all that sub content that confuses the detector. Two fixes worth knowing:

High-pass the sidechain source. A high-passed kick triggers more cleanly because the detector is not fighting the very frequencies you are trying to protect.
Use a trigger track. A short click or pulse aligned with the kicks gives consistent triggering no matter how the kick dynamics move. I keep a MIDI-clip-triggered sidechain in my template for exactly this reason. The compressor responds to notes rather than audio, which removes false triggers and locks the timing.

That MIDI-triggered approach is the one I would defend hardest. Once you have heard a sidechain that fires perfectly every time, going back to audio detection on a busy kick feels like guesswork.

Multiband, or the surgical option

Full-range ducking pulls the whole bass down, including the upper harmonics that carry the note’s pitch and attack. Multiband sidechain only compresses the band that actually conflicts. The low band ducks hard, the mids and up stay put, and you keep the bass’s definition while still making room for the kick.

Trackspacer does this automatically. It analyses which frequencies the kick occupies and reduces only those ranges in the bass. On a busy IDM arrangement where the bass is doing melodic work up top, that is a real improvement over a flat duck. On a straight club track where the bass is a single sine, full-range sidechain is simpler and sounds the same.

Ducking is not the same as sidechain compression

Worth a note on terminology, because it changes what tool you reach for. Ducking attenuates by a fixed range, while sidechain compression creates variable attenuation that follows the source signal. Ducking is often used in place of mirrored EQ to fight masking, which is exactly the kick-versus-bass case: subtle ducking under the kick that resembles gentle sidechain pumping.

It is also used well outside the kick-and-bass question. Ducking a reverb or delay send keyed to a dry track keeps the effects audible only when the source pauses. That is the move behind a lyric sitting clear in a wet mix on something like Céline Dion’s “The Power Of Love”, where the reverb blooms into the gaps. Same principle, different target. If your bassline has a long reverb tail smearing its own transients, duck the reverb instead of the bass and leave the low end intact.

The version we keep coming back to

For an independent techno record where the kick and bass are meant to read as one locked unit, our default is a MIDI-triggered sidechain on the bass, high-passed, with ratio and threshold set for 5 to 8 dB of reduction and auto-release. Bass ducks on the kick, comes back hard, kick stays punchy, no mud.

For electro and breaks where the bass needs its own melodic identity, we switch to multiband or Trackspacer-style frequency-dependent ducking so the top of the bass keeps ringing through the kick hit.

For anything rock-adjacent, country, or pop, keep the duck transparent: 2 to 4 dB and you are done. If you can hear it pumping, it is the wrong move for that genre. The technique should serve the arrangement, not announce itself.

One thing I would tell any producer starting out: get the arrangement right first. Write the bass so it does not fight the kick, then use sidechain to clean up the collisions that remain. The duck is a scalpel. It is not a substitute for a bassline that has nowhere to sit.