ferraus multiband

Multiband compressor

Synopsis

ferraus multiband <input> [options] [-o <output>]

Splits the signal with 4th-order Linkwitz-Riley crossovers (bands sum flat), compresses each band, and sums them. Per-band --threshold, --ratio, --attack, --release accept one value for every band or a comma list (low to high; a short list repeats its last value). Defaults are a gentle 2:1 on each band, with slower times on lower bands. --bands 4 picks 120Hz,2kHz,10kHz crossovers; --limiter adds a true-peak limiter at the output.

This command is also an fx stage and a pipeline op: ferraus fx in.wav -o out.wav --fx "multiband:key=value".

Examples

Gentle three-band compression

ferraus multiband mix.wav -o mb.wav

Audition-style 4 bands plus limiter

ferraus multiband master.wav --bands 4 --limiter --threshold -24dB,-20dB,-20dB,-18dB --ratio 3:1,2:1 -o mb4.wav

Three custom bands: hold down boominess and harsh highs harder than the mids

ferraus multiband vox.wav --crossovers 250Hz,4kHz --threshold -24dB,-18dB,-26dB --ratio 3:1,2:1,4:1 -o vox_mb.wav

Two bands split at 1 kHz: compress only the lows and leave the string noise alone

ferraus multiband bass.wav --bands 2 --ratio 4:1,1:1 --makeup 2dB -o bass_mb.wav

Options

Flag	Type	Default	Meaning
`--crossovers`	list	`150Hz,3kHz`	Crossover frequencies, ascending; N crossovers make N+1 bands
`--bands`	integer	—	Band count with default crossovers (2: 1kHz; 3: 150Hz,3kHz; 4: 120Hz,2kHz,10kHz; 5; 6) Range: 2..6.
`--threshold`	list	`-20dB`	Per-band threshold(s) in dB
`--ratio`	list	`2:1`	Per-band ratio(s)
`--attack`	list	`auto`	Per-band attack time(s); auto = 20 ms (lowest) to 5 ms (highest)
`--release`	list	`auto`	Per-band release time(s); auto = 200 ms (lowest) to 80 ms (highest)
`--makeup`	gain	`0dB`	Output gain after the bands are summed
`--limiter`	flag	—	Add a true-peak output limiter
`--limiter-ceiling`	gain	`-1dBTP`	Ceiling of the output limiter
`--mix`	percent	`100%`	Dry/wet balance: 0% returns the input unchanged, 100% is fully processed

Global options

Every command also accepts the global options (-o, --json, --dry-run, --overwrite, --progress, ...). See Global options.

Exit codes

Code	Meaning
0	Success
1	Processing failed
2	Usage or parameter error
3	Input missing or unreadable
4	Unsupported format or codec
8	Cancelled
70	Internal error (bug)

Common mistakes

Forgetting that outputs are never overwritten: pass --overwrite or a new -o path when re-running.
Gains need a unit when not in dB: 0.5x is a factor, -6 and -6dB are decibels.

For models

MCP tool: ferraus_multiband
Schema: ferraus schema multiband
Pipeline: { op: multiband, args: { ... } } (flag names with _ instead of -)
fx stage: yes

{"command": "multiband", "defaults": {"crossovers": "150Hz,3kHz", "threshold": "-20dB", "ratio": "2:1", "attack": "auto", "release": "auto", "makeup": "0dB", "limiter_ceiling": "-1dBTP", "mix": "100%"}}