Multiband compression is compression that works on separate frequency bands at the same time, instead of squashing the whole signal as one. It splits the sound into ranges, usually lows, mids and highs, and puts an independent compressor on each one, so you can calm a boomy low end or a harsh top without touching the rest. It is powerful, and easy to overuse.
It is really several compressors plus a set of crossovers that divide the spectrum. The band counts and figures here are typical, not fixed, and every mix is different, so treat them as a starting point rather than a rule.
Multiband compression is compression applied to separate frequency bands at once, rather than to the whole signal together. A normal, single-band compressor turns the level down whenever the sound as a whole gets too loud, which means a heavy kick drum can trigger it and duck the vocal and everything else along with it. A multiband compressor first splits the sound into bands, then compresses each one on its own, so the loud low end is controlled while the mids and highs that were already fine are left alone.
Think of it as a stack of compressors, one per band, fed by a set of filters that decide where each band begins and ends. That is really all it is: several compressors plus a crossover. Because each band has its own threshold and its own amount of gain reduction, you can be firm in one range and gentle, or completely hands off, in another.
A close relative is dynamic EQ, which does a similar job from the other direction, boosting or cutting a chosen frequency only when it crosses a level rather than all the time. The two overlap a lot, and for a single problem spot a dynamic EQ is often the more surgical choice.
A multiband compressor is not a special effect. It is a crossover feeding several ordinary compressors. Everything it can do, one band could do on its own with a plain compressor and a filter. The point is doing it to three or four ranges at once, each with its own settings, under one set of controls.
It splits the incoming audio into frequency bands with crossovers, runs an independent compressor on each band, then sums them back together. The crossover points are the frequencies where one band hands over to the next, for example a low band up to a few hundred hertz, a mid band above that, and a high band on top. Two crossovers make three bands, three make four. You set those split points, then set threshold, ratio, attack and release separately for every band, exactly as you would on a single compressor.
| Control | What it does | A place to start |
|---|---|---|
| Crossover points | The frequencies where the sound is split into bands. Two crossovers make three bands, three make four. | Place them between the ranges you want to treat separately, not on top of them |
| Threshold, per band | The level in that band above which its compressor starts turning down. Anything below it passes untouched. | Lower it until only the loud moments in that band show gain reduction |
| Ratio, per band | How hard that band is turned down once it is over the threshold. Higher ratios squeeze harder. | Gentle, around 2:1 to 4:1, to keep it natural |
| Attack, per band | How quickly that band clamps down once its level crosses the threshold. | A little slower on low bands, they move slower than highs |
| Release, per band | How quickly that band lets go once its level drops back under the threshold. | Too fast can pump within that band, so ease off |
| Gain reduction meter, per band | Shows how many dB each band is being turned down at any moment. | A few dB per band is usually plenty |
Because the controls repeat for every band, a multiband compressor has a lot of knobs, but each band behaves like the plain compressor it is built from: threshold and ratio set how much, attack and release set how fast. Our guide to compression walks through those controls in detail, and they mean the same thing here, just applied one band at a time.
The one control unique to multiband is the crossover. Set the split points so each awkward range sits inside its own band, away from the clean parts you want to leave alone. If a boomy low end and a harsh upper mid are the two problems, put a crossover above the boom and another above the harshness, so you can work on each without disturbing what sits between them.
Reach for it on a full mix or a master, or any time one frequency range misbehaves while the rest is fine. It earns its place when the problem is tied to a band rather than to the whole signal, which is why it lives mostly on the mix bus and in mastering. The common jobs:
So it fits mastering and the mix bus, and fixing a specific problem band on a single track when a plain compressor would clamp too much of the sound. Our guide to mastering covers where a step like this sits in the wider chain, and why less is usually more that late in the process.
Multiband compression is a problem solver, not something to reach for out of habit. It shines when a range is both too loud and too dynamic to catch any other way. If the range is simply too loud all the time, an EQ cut is cleaner, and if the whole part is uneven, a plain compressor is simpler. Pick the tool the problem actually calls for.
The big one is using it when you do not need it, and using too much of it. Multiband compression is powerful, and that power makes it easy to flatten a mix, blur the joins between bands, and chase problems a simpler tool would solve in one move. A few habits keep it honest.
Multiband compression is a fix for a narrow kind of problem, not a stage every mix needs. Most of the time a plain compressor or an EQ is the better first tool, and you move to multiband only when a range is both too loud and too dynamic to catch any other way. Few bands, small amounts, always compared at a matched level.
We do not sell a multiband compressor, and this page is tool-agnostic on purpose. But multiband compression is often reached for to rescue a mix that is fighting itself, where two parts crowd the same frequency range and one has to be squeezed to make room for the other. The Collection is our three instruments together, ARGISH, SILT and REHEAT, with three separate licence keys. They are voiced to sit in their own frequency range from the start, so a mix built with them has less of that fighting to fix later. ARGISH is a self-playing chord synth, SILT is a tape-loop instrument, and REHEAT writes acid lines. Every one ships as AU, VST3, AAX and a standalone app on macOS, signed and notarized, and a VST3 on Windows.
You can hear one free in your browser first, no install and no account, then decide.
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