What it is and how it works
A multiband compressor splits the signal into 2–6 bands with a crossover, compresses each band independently and sums them back. This way you can control the bass without making the highs pump, or tame the harshness at 3 kHz only when it explodes. It is powerful but risky: every band changes the tonal balance dynamically, and heavy use makes the sound unnatural.
Crossover
- Typical split points (4 bands): below 100–120 Hz (sub/bass), 120 Hz–500 Hz or 1 kHz (body), 1–5 kHz (presence), above 5–6 kHz (brilliance). With 3 bands: < 150 Hz, 150 Hz–4 kHz, > 4 kHz.
- Filter type: IIR (Linkwitz-Riley or Butterworth, zero latency, small phase rotation at the crossover) or linear phase FIR (no rotation, latency and pre-ringing). Fruity Multiband Compressor offers IIR (Butterworth 24 dB/oct) and linear FIR (recommended by the manual for mastering). Frequency Splitter (2 or 3 bands, slopes from 6 to 96 dB/oct, Normal or Linear Phase) lets you send the bands to different mixer tracks.
- Watch out for gaps: in Fruity Multiband Compressor the four cutoffs are independent and can leave frequencies out; verify that the bands are perfectly crossed over (the cutoffs “snap” when they are).
Parameters per band
- Threshold: in Fruity Multiband Compressor from 0 to −60 dB.
- Ratio: 1.5–3:1 for control; 4–8:1 for specific problems (ratio up to ∞:1).
- Attack: proportional to the band. Lows: 10–30 ms (attacks that are too fast distort). Mids: 5–20 ms. Highs: 1–5 ms. In Fruity Multiband Compressor 0.1–100 ms.
- Release: lows 100–300 ms, mids 80–200 ms, highs 30–100 ms (10–1000 ms in the FL plugin).
- Knee: soft (Fruity MB: 0% soft – 100% hard).
- Gain: make-up per band: it also becomes a static EQ.
- Solo/Bypass/Mute of the band (A/M/B in Fruity MB): always listen to the isolated band to understand what you are compressing.
- External sidechain per band (Pro-MB, Maximus with sidechain): ducking of the bass only.
- Upward/downward: some multibands also compress upward (see “Upward compression”).
Maximus (FL Studio)
Three bands (Low, Mid, High) plus a wideband Master band; for each band: drawable compression curve (even below the threshold), saturation (two types), stereo separation, look-ahead. The manual recommends it mainly as the last effect on the Master to maximize, and suggests Fruity Limiter or Fruity Compressor for individual sounds. The “phase-free” mix between bands and Master also allows parallel/NY compression. Soundgoodizer is a simplified interface with Maximus presets.
When to use it and on what
- Bass/808: control the 40–100 Hz band, which varies a lot from note to note (ratio 3:1, attack 20 ms, release 150 ms, GR 2–4 dB).
- Vocal: tame the 200–400 Hz that swells on some notes (proximity effect) or the 2–4 kHz that gets harsh on high notes; the de-esser is a one-band multiband.
- Distorted guitars: 150–300 Hz that swells with palm mutes (Metal), harsh 2–4 kHz.
- Drum bus: control the kick in the lows without compressing cymbals.
- Music bus: low band in sidechain from the kick (ducking in the lows only).
- Mastering: slight corrections (1–2 dB) on a band that pops out in certain sections; never as a generic “improve the sound”.
- Often a dynamic EQ does the same job with fewer side effects: prefer it for narrow problems.
Starting settings
| Use | Band | Ratio | Attack | Release | GR |
|---|---|---|---|---|---|
| Uneven 808/bass | 30–120 Hz | 3:1 | 20–30 ms | 150–250 ms | 2–4 dB |
| Muddy vocal on low notes | 150–400 Hz | 2–3:1 | 10 ms | 100 ms | 2–3 dB |
| Harsh vocal on high notes | 2–4 kHz | 3:1 | 3–5 ms | 60–100 ms | 2–4 dB |
| Palm-muted guitars | 120–300 Hz | 3:1 | 10 ms | 80 ms | 2–4 dB |
| Master: bass control | < 120 Hz | 1.5–2:1 | 30 ms | 200 ms | 0.5–1.5 dB |
| Master: chorus harshness | 2–6 kHz | 1.5–2:1 | 10 ms | 100 ms | 0.5–1.5 dB |
By genre
- Trap, drill: useful on the 808 (sub stability from note to note) and on aggressive vocals.
- Metal: guitars and bass with palm mutes; triggered kick.
- EDM: OTT and “extreme” multiband as a sound design effect on synths (see upward).
- Pop mastering: light, only if needed.
Common mistakes
- Compressing all the bands “because they're there”: the spectrum flattens and the mix loses character.
- Crossovers that are too steep or misaligned: gaps and phase shifts at the crossover (listen with all the bands bypassed: it must be identical to the original).
- Attack too fast in the low band: waveform distortion.
- Using the multiband to fix an unbalanced mix: go back to the tracks.
- Forgetting that per-band make-up is an EQ: always compare at equal volume.
How to hear it
- Solo the band and lower the threshold: you should clearly hear the problem (mud, harshness) and then its reduction.
- With all the bands active but ratio 1:1 and gain 0, the plugin must be transparent (crossover test).
Starting settings
| Parameter | Value | Why |
|---|---|---|
| Number of bands | 2–4 | More bands = more risk of coloration. |
| Typical crossovers | 120 Hz, 1 kHz, 5 kHz | Separation between sub, body, presence, brilliance. |
| Attack per band | Lows 10–30 ms, mids 5–20 ms, highs 1–5 ms | Lows have long cycles: fast attacks distort them. |
| Release per band | Lows 100–300 ms, mids 80–200 ms, highs 30–100 ms | Musical recovery. |
| GR | 1–4 dB per band (0.5–1.5 in master) | Invisible control. |
| Crossover filter | IIR for mixing, linear FIR for mastering | Phase versus latency. |
Frequencies to watch
| Range | What to do |
|---|---|
| 30–120 Hz | Low band: stabilizes sub and 808 from note to note; slow attacks. |
| 150–400 Hz | Note-dependent mud (vocal, guitars, piano). |
| 2–5 kHz | Harshness that explodes on high notes or in choruses. |
| 5–10 kHz | Sibilance/fizz: the job of the de-esser or a fast band. |
Example chain
| Step | Tool | Settings | Why |
|---|---|---|---|
| Corrective EQ | Fruity Parametric EQ 2 / Pro-Q | Static problems | Multiband only for the dynamic ones. |
| Wideband compression | Fruity Compressor / Pro-C 2 | GR 2–4 dB | Overall level. |
| Multiband | Fruity Multiband Compressor / Maximus / Pro-MB / Waves C4-C6 / Ozone Dynamics | One or two active bands | Problems that depend on frequency and time. |
| Alternative | Dynamic EQ (Pro-Q, TDR Nova) | Narrow band | Fewer side effects for narrow problems. |
| Bands on separate tracks | Frequency Splitter → mixer tracks or Patcher | 2–3 bands, Linear Phase if needed | Different processing (e.g. saturation only on the 808's highs). |
How to check the result
- With ratio 1:1 and gain 0 on all bands, the null against the original (phase inversion) is below −60 dB: transparent crossover.
- Average track spectrum unchanged within ±1 dB outside the bands you want to control.
- 808 low band: level variation between notes reduced to 2–3 dB (short-term with a low-pass filter or analyzer).
- In mastering: GR per band no more than 1.5–2 dB at the loudest points.