ferraus echo

Multi-tap echo with per-repeat filtering

Synopsis

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

Adds --taps repeats spaced --time apart (a beat fraction such as 1/4 follows --bpm, else 120 BPM; or a time such as 375ms). Each repeat is --feedback quieter than the one before and passes through --tap-eq once more, so repeats get progressively darker. --pingpong alternates repeats between left and right (a mono input becomes stereo). The output keeps the input length.

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

Examples

Quarter-note echoes at 96 BPM

ferraus echo vox.wav --bpm 96 -o echo.wav

Telephone-like ping-pong repeats

ferraus echo gtr.wav --taps 6 --time 375ms --feedback 55% --tap-eq highpass:300Hz,lowpass:3kHz --pingpong -o echo.wav

A single slapback repeat, rockabilly style

ferraus echo vox.wav --taps 1 --time 110ms --feedback 35% -o slap.wav

Long, bright half-note echoes with no darkening filter

ferraus echo announcer.wav --taps 8 --time 1/2 --bpm 80 --tap-eq none -o canyon.wav

Options

Flag	Type	Default	Meaning
`--taps`	integer	`3`	Number of repeats Range: 1..32.
`--time`	time	`1/4`	Spacing between repeats: a beat fraction (1/4, 1/8D) or a time (375ms)
`--feedback`	percent	`40%`	Level of each repeat relative to the previous one, in percent
`--tap-eq`	list	`lowpass:4kHz`	Filter(s) applied once more to every repeat, e.g. lowpass:4kHz or none
`--pingpong`	flag	—	Alternate repeats between left and right
`--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.
Beat-based times (4b, 1/4) need a tempo: pass --bpm or write 4b@120.
Percentages accept 80% or the fraction 0.8; a bare 80 means 80x, not 80%.

For models

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

{"command": "echo", "defaults": {"taps": "3", "time": "1/4", "feedback": "40%", "tap_eq": "lowpass:4kHz", "mix": "100%"}}