ferraus expand

Downward expander

Synopsis

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

What it does

Turns quiet passages down further: every dB below the threshold becomes 'ratio' dB. The gentle alternative to a gate.

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

Examples

Reduce room noise between phrases

ferraus expand vo.wav -o vo_exp.wav

Stronger expansion

ferraus expand drums.wav --threshold -30dB --ratio 3:1 -o tighter.wav

Very gentle, slow expansion that lowers room tone without chopping word endings

ferraus expand podcast.wav --threshold -45dB --ratio 1.5:1 --release 250ms -o podcast_exp.wav

Gate-like expansion with a fast attack so the tom's hit is not softened

ferraus expand tom.wav --threshold -35dB --ratio 4:1 --attack 1ms -o tom_exp.wav

Options

Global options

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

Exit codes

Common mistakes

• Forgetting that outputs are never overwritten: pass --overwrite or a new -o path when re-running.
• Beat-based times (4b, 1/4) need a tempo: pass --bpm or write 4b@120.
• Gains need a unit when not in dB: 0.5x is a factor, -6 and -6dB are decibels.

For models

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

{"command": "expand", "defaults": {"threshold": "-40dB", "ratio": "2:1", "attack": "5ms", "release": "100ms", "mix": "100%"}}