ferraus lowpass

Low-pass filter

Synopsis

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

What it does

Removes content above --freq. --order 2 is 12 dB/oct; higher orders are Butterworth (6 dB/oct per order). --q shapes the corner of an order-2 filter.

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

Examples

Tame harsh highs

ferraus lowpass hats.wav --freq 9kHz -o darker.wav

Resonant low-pass

ferraus lowpass synth.wav --freq 800Hz --q 4 -o reso.wav

Steep 24 dB/oct cut that keeps a bass out of the vocal range

ferraus lowpass bass.wav --freq 2kHz --order 4 -o bass_lp.wav

Telephone-style top cut

ferraus lowpass voice.wav --freq 3.4kHz --order 6 -o phone.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.

For models

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

{"command": "lowpass", "defaults": {"freq": "12kHz", "order": "2", "q": "0.707", "mix": "100%"}}