Blue Beard Audio — Audio plugins, built independently

Greenbelt Delay

Bluebeard / GB‑01

A stereo delay with the look and feel of a well-loved pedal. Dial in a sound with four main controls, then pick one of twelve modes and one of three models to shape how the repeats behave. Ten parameters, one panel, no hidden pages.

In development — version 0.1.0

Greenbelt Delay is being built and tested now, as VST3, Audio Unit and a standalone app. Downloads and final system requirements will be posted here once it is ready.

Formats: VST3, Audio Unit, Standalone
Platforms: Windows 10+, macOS 10.13+ (Apple Silicon and Intel)
Channels: Mono and stereo
Processing: 32-bit float, 2× oversampled
Delay range: 53–2235 ms on the knob, up to 5000 ms
Parameters: 10, all automatable

The panel

Four knobs, three switches

Everything that shapes the sound sits on one face, so you can set it by hand the way you would a pedal. A display between the switches shows the value you are touching, and otherwise the delay time the engine is really using.

Mix

A linear crossfade between your dry signal and the repeats, from a hint of space to fully wet. At 50% the dry signal is 6 dB down, so on a send set it to 100%.

0–100% · default 35%

Repeat

How much of the delay feeds back. Digital tops out at unity and holds; Tape and Analog pass unity at about 95% and self-oscillate, kept in check by the saturator.

0–100% · default 35%

Time

The delay time. The taper puts 500 ms at the center of travel, so the short and medium times get the most room. Grayed out while Sync is on. Changes glide over 80 ms like a tape machine.

53–2235 ms · default 400 ms

Mod

Depth of delay-time modulation. The rate and shape belong to the model: slow chorus on Digital, fast vibrato on Analog, wow, flutter and drift on Tape. It pitch-modulates the tail and widens the repeats.

0–100% · default 0%

Sync

Lock the delay to your DAW tempo, or switch it off and set the time in milliseconds. On by default.

Trails

Let the repeats ring out when you bypass, instead of cutting them off. Off clears the buffer so every re-entry starts clean.

Low Latency

Turns off oversampling: zero reported latency and roughly half the CPU. Set it once rather than automating it, because it clears the tail.

Bypass footswitch

The footswitch is the host bypass parameter, so your DAW’s own bypass button and the pedal move together. The lamp above it is lit when active. Bypass is smoothed over 10 ms to avoid clicks.

Made to be played

Drag a knob up or down, use the mouse wheel, or click and use the arrow keys. Knobs ease toward their target, and the window resizes from 805×489 up to 1610×977 without distorting.

A display you can trust

Hover a control to see its own value. Otherwise the display reads the effective delay time and the tempo it came from, for example TIME 500 ms / 120 BPM, or BYPASSED.

Twelve modes

Pick the pattern

The Mode selector sets the rhythm and behavior of the repeats. The first six are note divisions, reading from the longest delay to the shortest. Slap gives the Time knob a short slapback range, and the last five change how the effect itself works.

Note divisions and slapback

Normal (1/4): Straight quarter-note repeats. The plain starting point, and the baseline for everything else.
Dotted 1/4: One and a half beats. The longest division, and the only one that can run past the knob’s printed maximum, to 3353 ms free-running.
1/4 Triplet: Three repeats across two beats. The most countable of the triplets, so it reads as a rhythmic figure.
1/8: Straight eighths, two repeats per beat. Reinforces the pulse, and forgiving at high feedback.
Dotted 1/8: Three sixteenths. The familiar pattern that falls between the beats and pushes against a straight part.
1/8 Triplet: Three repeats per beat. Fast and blurry, best with Analog and moderate feedback.
Slap: The whole Time knob remapped to 10–150 ms. Synced, it becomes a sixteenth note. Keep Repeat low.

Behavior modes

Swell: Each new note fades in from silence over 350 ms, like a volume pedal. It swells the dry signal as well, so use a send for wet-only.
Sweep: A resonant low-pass sweeps 250–3500 Hz inside the feedback loop, so every circulation is filtered at a different point. Feedback sets how much of it you hear.
Ducking: Repeats drop by up to 16.5 dB while you play and return in the gaps, so you can run a much higher Mix and stay clear of a lead vocal.
Ping Pong: Input goes to the left channel and each channel feeds the other, so repeats alternate left and right. The dry path keeps its width.
Reverse: Repeats are read backwards in windowed segments. Keep Repeat low for a clean reverse; Mod has no effect here.

Three models

Choose the character

The Model selector decides what the repeats are made of, independent of the pattern you picked. It sets the filtering and saturation in the feedback path, the modulation shape and how far Repeat can push. Because every repeat is voiced once per trip around the loop, the differences grow with feedback.

Tape

Warm, slightly dark and a little unstable. Repeats soften and darken as they travel, and wow, flutter and random drift mean no two repeats land in quite the same place. The most forgiving model at high feedback.

Digital

Clean, full-range and stable. Repeats stay close to what you played going in, with only a DC-blocking high-pass in the loop. At 100% feedback the loop holds for minutes, which suits sound-on-sound.

Analog

Bucket-brigade character: dark, narrow and compressed. Low end thins out with every pass, so the tail sits under a part instead of competing with it. The most aggressive saturation of the three.

Model comparison
	Tape	Digital	Analog
High-pass	60 Hz	10 Hz	120 Hz
Low-pass	4800 Hz, 6 dB/oct	None	3000 Hz, 12 dB/oct
Saturation	tanh, gentle	Soft limit above full scale	tanh, hardest
Feedback ceiling	Oscillates near 95%	Holds at unity	Oscillates near 95%
Mod character	Wow, flutter and drift	0.7 Hz chorus, ±3 ms	4.5 Hz vibrato, ±0.9 ms

These are voicing targets, not emulations of specific hardware units.

Tempo sync

Locked to the grid, or not

With Sync on, the delay time comes from your host’s tempo and the Time knob steps aside. The six division modes and Slap multiply the quarter note; the five behavior modes all use a plain quarter note.

Delay time in milliseconds at common tempos, Sync on
BPM	1/4	Dotted 1/4	1/4 Trip	1/8	Dotted 1/8	1/8 Trip	Slap (1/16)
80	750.0	1125.0	500.0	375.0	562.5	250.0	187.5
100	600.0	900.0	400.0	300.0	450.0	200.0	150.0
120	500.0	750.0	333.3	250.0	375.0	166.7	125.0
140	428.6	642.9	285.7	214.3	321.4	142.9	107.1
174	344.8	517.2	229.9	172.4	258.6	114.9	86.2

Phase is yours. Sync sets the interval, not the alignment. Repeats follow what went in, not the bar line.
Tempo changes glide. A ramped tempo bends the pitch of the tail over 80 ms, which can be a feature or a nuisance.
No tempo, no sync. If the host does not report one, the last tempo it saw is used, or 120 BPM. The standalone app never receives one.
Floor of 20 BPM, which caps a synced quarter note at 3000 ms.

Under the hood

How it behaves

One delay line, one feedback node, and a voicing stage between them. The manual documents the real constants the engine uses, not approximations.

Voiced from the first repeat

The model’s filtering and saturation sit before the write into the line, so even the first repeat is colored. The output tap is pre-feedback, so Repeat changes how many repeats follow, not how loud the first one is.

Tape-style time changes

The read tap is a 4-point cubic Hermite interpolator and the time glides over 80 ms, so turning Time, switching mode or changing tempo transposes what is in the line. Sweep Time during a tail for a tape-stop.

2× oversampling

The engine runs at twice the host rate through a half-band FIR so the saturators do not alias. The latency is a whole number of samples, so host delay compensation is exact. Low Latency removes it.

Bypass and trails

Bypass returns the dry path to unity and stops new input. With Trails on, the tail decays naturally. With it off, the wet path fades over 10 ms and the buffer is cleared. The plugin reports a 10-second tail to the host.

Saved with the session

All ten parameters are saved and automatable, and VST3 presets work through your host. There is no factory preset library. The contents of the delay line are not saved.

Small and offline

No installer, no copy protection and no network access. Copy the bundle to your plugin folder, rescan, and it appears as Greenbelt Delay under Blue Beard Audio.

Starting points

Sounds to begin with

A few settings from the manual, each chosen for a reason rather than just a number.

Vocal delay

Ducking, Analog, Sync on at Dotted 1/8, Mix 45–60%, Repeat 40–50%. The repeats step back while the vocal is present.

Rockabilly slap

Slap, Tape, Sync off, Time at 80–90% of travel, Repeat 0–15%, Mod 15–25%. One repeat with a little drift.

Ambient wash

On a send: Mix 100%, Sweep, Tape, Repeat 70–85%, Mod 40–60%, Trails on. The in-loop filter keeps the tail moving.

Sound-on-sound hold

Digital, Repeat 100% and a Time of one to two seconds. Play a phrase and it sustains for minutes. Pull Repeat back to let it go.

Reverse lead

Reverse, Repeat 15% or less, Mix around 50%, with a long time. Short times turn into a granular stutter.

Swelled pads

On a send with Mix at 100%: Swell, Analog, Repeat near 60%. Feed it a plucked part with clear gaps between notes.

Questions or feedback?

Get in touch directly — every message comes to me, and I read all of them.

inquiries@bluebeardaudio.co