Press play and your low end is a coin flip: on some bars the kick punches and the bass growls underneath it, on others the two swallow each other and the bottom octave turns to mush. You searched for how to mix kick and bass because the two loudest elements in your track are fighting over the same 40 to 90 Hz, and no amount of fader riding settles the fight. The fix is a sequence of four decisions, not a magic plugin: pick one owner for the sub, tune both elements to the key, carve the handover with EQ, and time the sidechain in milliseconds. Make those calls once and the relationship holds for every track you mix afterwards.
Decide who owns 40 to 90 Hz before you touch a plugin
Only one element can hold the sub at a time. Two full-range signals stacked between 40 and 90 Hz cancel on some hits, sum on others, and eat 4 to 6 dB of headroom while sounding weaker than either one alone. So the first move is a decision, and genre logic makes it for you. In four-on-the-floor music, the kick is the anchor: it owns 45 to 90 Hz and the bass tucks in above it from roughly 90 to 250 Hz. That is the standard layout in techno production and most house, where the kick hits every beat and needs an uncontested bottom. In bass-led music the roles flip: the 808 or sub line owns 30 to 60 Hz and the kick contributes click and body from 60 Hz upward with a short decay. That is how drum and bass tracks and most dubstep, halftime, and 808-driven hip-hop are built, because the bassline is the lead instrument and the kick is percussion. Make the call before you open an EQ, because every move below depends on it.
Tune the kick and bass to the same key, or they beat against each other
A kick drum has a pitch. Most sampled kicks sit somewhere between 40 and 60 Hz at the fundamental, and when that pitch lands 2 to 3 Hz away from the root of your bassline, the two frequencies beat against each other at the difference rate. You hear it as a slow wobble in the low end that no EQ cut removes, because the problem is tuning, not balance.
Find the kick's fundamental with a spectrum analyzer: solo the kick, loop it, and read the lowest strong peak. A peak at 49 Hz is a G, 55 Hz is an A, 43.7 Hz is an F. If that note is not the root or the fifth of your track's key, repitch the kick until it is. The bass is already locked to the key by the melody, so the kick is the one that moves. A semitone of repitch is inaudible as a timbre change on almost every kick, and it turns the low end from two arguing frequencies into one chord.
Carve the handover with EQ: 2 to 4 dB is enough
With ownership decided and tuning matched, the EQ job is small and specific. In a kick-owns layout, high-pass the bass at 80 to 100 Hz with a 24 dB per octave slope, then cut the bass another 2 to 3 dB at the kick's exact fundamental with a Q of around 2. On the kick, cut 2 to 4 dB between 150 and 300 Hz with a wide Q, because that is where the bass harmonics carry the note and the kick body only adds boxy weight there. Shaping the kick itself, the click around 3 to 5 kHz and the knock at 100 to 200 Hz, is its own job, covered in the guide to EQing a kick drum.
In a bass-owns layout, mirror the moves: high-pass or shelf the kick down 3 to 6 dB below 50 Hz, shorten its decay so the tail leaves before the sub note blooms, and dip the bass 2 dB around the kick's punch region, usually 60 to 90 Hz. Resist bigger cuts. A 6 dB notch in either element leaves an audible hole on solo systems, and the sidechain in the next step handles the remaining overlap dynamically.
How to sidechain kick and bass: 2 to 4 dB for a clean handover, 6 dB and up for pumping
Once ownership, tuning, and the EQ handover are set, here is how to sidechain kick and bass so the two stop overlapping. Sidechain compression triggered from the kick ducks the bass only in the milliseconds where the kick actually needs the space, finishing what the static EQ started. For a transparent handover, aim for 2 to 4 dB of gain reduction, an attack of 0.1 to 1 ms so the duck lands with the transient, and a release timed to the gap between hits. At 128 BPM a sixteenth note is 117 ms, so a release of 80 to 120 ms brings the bass back to full level before the next event in the groove. At 174 BPM that window shrinks to 86 ms, so set the release at 40 to 60 ms instead.
The pumping aesthetic is the same tool pushed harder: 6 to 10 dB of gain reduction with a release of 200 to 300 ms, long enough that the bass audibly swells back between kicks. Pumping is a sound design choice, common in melodic techno and big-room house, and it only works when the whole mix breathes with it, so duck the pads together with the bass rather than the bass alone. Whichever style you choose, check the result the honest way: render an eight-bar loop of kick and bass alone, then upload the bounce to TrackSensei and look at the low-end energy reading. The meter settles arguments your monitors keep losing.
Fold to mono and flip polarity before you blame the EQ
When kick and bass still sound thin together after the EQ and sidechain work, the problem is phase, not balance. Collapse the mix to mono and listen to the low end. If the bottom drops in level or a specific note disappears, the two elements are partially cancelling. The fastest test is the polarity switch: flip the bass channel's polarity and keep whichever position sounds fuller at 50 Hz. That one click recovers 2 to 3 dB of low end in a surprising number of mixes.
Then lock the foundation down. Keep everything below 100 to 120 Hz mono, either with a stereo imaging plugin set to collapse the lows or by avoiding stereo wideners on the bass patch entirely. Wide sub information cancels on club systems, which sum the low end to mono at the crossover, so a stereo 50 Hz that sounds huge on headphones arrives at the venue 3 to 6 dB down.
The two habits that keep kick and bass clashing
First habit: boosting both elements at the same frequency. You boost the kick 3 dB at 50 Hz because it feels soft, then boost the bass 3 dB at 50 Hz because now it feels buried, and the sum is 6 dB of buildup at one frequency plus a compressor or limiter downstream working overtime. When both elements feel weak, the answer is gain staging, never a matching pair of boosts. Cut the loser at the contested frequency instead.
Second habit: a sidechain release set so long it swallows the groove. When the release stretches past the gap between hits, the bass never returns to full level, offbeat bass notes get clipped before they speak, and the track feels like it drags even though the tempo is right. Halve the release, listen to the offbeats, and tighten from there. Both habits come from mixing the low end in solo, and the cure is the same one that runs through the full mixing guide: judge every low-end move with the whole arrangement playing.
The hard part of all of this is that 40 to 90 Hz is exactly the range most rooms and headphones report least honestly, so you end up guessing at the one relationship the entire mix stands on. If you want numbers instead of guesses, upload your track to TrackSensei and read the low-end section. It measures the kick and bass relationship and your overall low-end balance against released tracks in your genre, so you can see whether the sub is owned, shared, or simply missing before you bounce the next version.