ferraus band-split

Split audio into frequency bands that sum back to the input

Synopsis

ferraus band-split <input> [options] [-o <output>]

Writes one file per band (roles band1..bandN, lowest first). Each crossover is a zero-phase Linkwitz-Riley (4th-order magnitude) split made by forward-backward Butterworth filtering, and each higher band is what remains after removing the lower ones, so the bands add back to the input exactly and have no phase shift.

Examples

Four bands: mix.band1.wav ... mix.band4.wav

ferraus band-split mix.wav

Two bands: drums.band1.wav (lows) and drums.band2.wav (highs)

ferraus band-split drums.wav --crossovers 200Hz -o drums.wav

Three bands (body, mids, air) written into bands/ for separate processing

ferraus band-split vox.wav --crossovers 300Hz,5kHz --outdir bands/

Five bands, with every output path listed in the JSON result

ferraus band-split mix.wav --crossovers 100Hz,500Hz,2kHz,6kHz --json

Options

Flag	Type	Default	Meaning
`--crossovers`	list	`120Hz,2kHz,8kHz`	Crossover frequencies, ascending (e.g. 120Hz,2kHz,8kHz gives four bands)

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.

For models

MCP tool: ferraus_band_split
Schema: ferraus schema band-split
Pipeline: { op: band-split, args: { ... } } (flag names with _ instead of -)
fx stage: no

{"command": "band-split", "defaults": {"crossovers": "120Hz,2kHz,8kHz"}}