Multiband Compression
Compressors that split the signal into frequency bands and process each independently.
A multiband compressor splits your signal into frequency bands — typically 3, 4, or 5 — and applies independent compression to each. The bass band can be heavily compressed for tightness while the highs are barely touched, or vice versa.
Used well, multiband is one of the most surgical tools in mixing and mastering. Used badly, it's a fast way to make a mix sound smaller and weirder.
How It Works
The signal is fed into a set of crossover filters that split it into frequency-based bands (e.g., below 120 Hz, 120–500 Hz, 500 Hz–4 kHz, above 4 kHz). Each band has its own compressor with independent threshold, ratio, attack, and release.
After compression, the bands are summed back together. If the crossovers are well-designed, the summed signal is identical to the input when no compression is applied.
When to Reach for Multiband
Loud low-end masking everything else. A bass-heavy drum loop or a kick drum that overpowers the mix. Compressing only the low band tames it without touching the rest of the spectrum.
Resonances on a dynamic source. A vocal that has a 250 Hz boxiness only on certain notes. A narrow multiband band can duck just those moments.
Mastering bus duty. A multiband on the master can correct tonal balance dynamically — slightly less low-end during loud passages, more high-end during quiet ones.
When Not To
Regular compression would do. If a vocal needs 3 dB of overall gain reduction, use a regular compressor. Multiband for the same task is overkill and risks introducing phase issues.
The problem is static (always there). If a frequency is always too loud, EQ it. Multiband is for dynamic problems — frequencies that are sometimes too loud.
The mix isn't the problem. Multiband on the master to fix a bad mix is a band-aid. The issue is in the individual tracks.
Multiband vs Dynamic EQ
These tools overlap heavily, but they're not the same:
- Multiband compression splits signal into bands, compresses each, then re-sums. Phase response is affected by the crossovers.
- Dynamic EQ boosts or cuts narrow bands when level exceeds threshold. No band-splitting, no re-summing — typically more transparent.
For surgical, frequency-specific dynamics, dynamic EQ is often the better choice. For broad tonal shaping, multiband compression has more character.
Common Mistakes
Too many bands. Most useful work happens in 2–4 bands. Five-band processing creates a lot of crossover artefacts for limited benefit.
Compressing every band. If only the low band has a problem, only compress the low band. Setting all four bands to compress equally is just inefficient broadband compression.
Mastering with multiband by default. Reach for it when a stereo bus compressor and an EQ haven't solved the problem. Not before.
Plugin Recommendations
Modern multiband with dynamic EQ mode. Six bands max, adjustable crossover.
View →Multiband module from Ozone. Includes machine-learning-based starting points.
View →Free dynamic EQ that doubles as a 4-band multiband. Genuinely good.
View →