Mixing low end for club systems

On studio monitors, a slightly loose low end is a detail. On a club rig moving serious air below 100 Hz, it's the whole track. The sub range carries most of the electrical energy in a dance record, and the big systems are merciless about three things: kick/bass conflict, stereo sub, and uncontrolled resonance. Here's how to get all three right at the mix stage.

Why clubs punish low end

A club PA is not a bigger version of your monitors. The subwoofers are usually driven from a summed mono feed below the crossover (commonly somewhere in the 80–120 Hz region), because bass wavelengths are longer than the room and stereo separation down there is physically meaningless — and because splitting sub energy across two amp chains wastes headroom. The system is also enormously more revealing: a 40 Hz resonance you can barely hear at home becomes a standing pressure wave, and a kick and bassline stepping on each other turns into low-mid mud that eats the whole mix's clarity. Every technique below follows from those physics.

Decide who owns the sub

The most common low-end mistake isn't tonal, it's territorial: kick and bass both trying to occupy the same octave at the same moment. Pick one owner for the true sub range (below ~60 Hz) and commit:

• Kick-owned sub — typical for techno and harder house: the kick's fundamental (often 45–55 Hz) is the biggest thing in the track, and the bassline lives an octave up, filtered below its fundamental so it never fights.
• Bass-owned sub — typical for DnB, dubstep, and bass music: a sustained sub bass carries the low end and the kick becomes a punchy transient centered higher (say 60–90 Hz) that cuts through rather than underpins.

Tune them, too. A kick with a defined pitch that clashes with the bassline's key reads as "something's off" even to listeners who can't name it. And high-pass everything else — pads, synths, vocals, FX — around 100–150 Hz. Individually inaudible rumble from ten channels sums into real energy that steals limiter headroom at the mastering stage.

Sidechain: making room in time

EQ separates kick and bass in frequency; sidechain compression separates them in time. The classic setup: a compressor on the bass, keyed from the kick, so the bass ducks a few dB for the few tens of milliseconds around each kick hit and swells back between hits. That does two jobs at once — it keeps the two biggest energy sources from summing into one giant peak (which is what forces limiters to pump), and, pushed further, it becomes the genre's signature groove.

Starting points, not rules:

• Ducking depth: 3–6 dB for transparent separation; 10 dB+ is an audible pumping effect — a legitimate stylistic choice, but choose it on purpose.
• Attack: fast, so the kick's transient gets out clean.
• Release: timed to the track — the bass should be fully back before the next kick. At 128 BPM, kicks land ~469 ms apart; releases in the 100–250 ms range usually breathe musically.
• Volume-shaper alternative: LFO/envelope tools that draw the duck shape directly are more predictable than a compressor and are standard practice now. Same principle, more control.

Keep the sub mono

Stereo width on a bass sound is great — on its sub frequencies it's a liability. If the left and right channels differ below the crossover, the club's mono sub feed sums them, and any out-of-phase content cancels: the bassline that felt huge on headphones physically loses level on the system. Wide detuned-saw basses and stereo chorus on the low octave are the usual culprits.

The convention: mono below roughly 100–150 Hz. Get there by splitting the bass into a mono sub layer plus a stereo top layer (the classic bass-music approach), or by putting a stereo imaging tool on the bus that collapses lows to mono while leaving width above the cutoff. Then verify with a correlation meter — a reading dipping toward negative on bass-heavy sections is the warning sign — and, more brutally, by hitting the mono button and listening to whether the low end keeps its weight. A mono fold-down check belongs in your premaster checklist anyway.

Control the resonances

Small rooms lie about specific bass notes, so a mix that sounded even at home often has one note booming and its neighbor missing. Defenses that don't require a treated room: check the bassline note by note against a spectrum analyzer to catch a fundamental that jumps several dB above its neighbors; use narrow cuts on the offenders rather than broad scoops; and compare against a commercial reference track's low-end curve at matched loudness — the reference has already survived club systems, so where your 45 Hz region towers over its curve, believe the reference, not your room.

Check it without a club

• Mono, quietly: the mix in mono at low volume tells you about balance and cancellation for free.
• Good headphones + analyzer: headphones bypass your room's bass lies; the analyzer catches what headphones under ~30 Hz miss.
• The car and the earbuds: not clubs, but different enough failure modes to expose kick/bass masking fast.
• A reference A/B at matched loudness — the single highest-information check on this list.

Low end that survives all four is low end a mastering chain can make loud without falling apart — which is precisely the difference between a master at −7 LUFS that pumps musically and one that just distorts.