SPOOL

A handheld-feel sampler / looper / field recorder inspired by the Teenage Engineering TP-7. Ships as a Windows VST3 plugin and a standalone app.

![Silver vertical handheld with vinyl reel, BPM display, waveform window, eight loop slots, and three big effect knobs.]

💛 Free & open source. If SPOOL earns a place in your workflow, a one-off Ko-fi tip or GitHub Sponsorship keeps the lights on. Zero pressure — the plugin stays free either way.

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What it does

• Drag-and-drop sampler — drop a WAV / AIF / FLAC / MP3 / OGG onto the panel, or load via the ↑ button.
• Live field recorder — REC captures from the default audio input; auto-loops on stop (RC-505 style).
• Loop region — drag across the waveform to set a custom loop; or pick a tempo-relative size (1/16 · 1/8 · 1/4 · 1/2 · 1B · 2B) that follows BPM.
• Eight loop slots — left-click to save, right-click to clear, or press 1-8 (number row or keypad) to recall.
• Tempo-synced effects — GHOST delay, FILTER LFO, ARP rate, and the loop-size grid all follow the internal BPM you set.
• Three big "JUICE" effect knobs — drag the icons to reorder the signal chain.
• MIDI sampler — play the loaded sample chromatically. 8-voice polyphony, C4 = root, works with any MIDI controller AND the on-screen keyboard.
• On-screen keyboard — toggle the ♪ KEYS pill to reveal a 2-octave keyboard with pitch wheel + mod wheel + ARP. Or just type a w s e d f t g y h u j k … to play notes; z / x shift octaves.
• Arpeggiator — engage ARP on the keyboard; held notes cycle in UP / DN / UPDN / RND patterns at a tempo-synced rate (mod wheel selects 1/4 → 1/32).
• LO-FI master mode — one-button "cassette" character: warm tanh saturation + bit-crush + HF rolloff, dialled with a dry/wet knob under the button. The whole chassis re-skins pink-purple with animated film grain when engaged.
• DJ scratching — grab the spinning vinyl and drag to scrub with a soft cartridge LP for authentic feel.
• Theme randomizer — double-click the SP-L wordmark for a fresh accent color.

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Controls

Transport

Control	Action
● REC	Capture from input. Click again to stop — auto-plays in loop mode.
▶ PLAY	Toggle playback. Also bound to spacebar.
■ STOP	Stop playback.

Tempo

Control	Action
BPM window	Drag vertically — up = faster, shift+drag = fine.
TAP	Tap 2-4 times in rhythm to lock tempo. Session resets after 2s silence.

Loop

Control	Action
Drag waveform	Highlight a custom loop region.
1/16 · 1/8 · 1/4 · 1/2 · 1B · 2B	Lock loop length in beats at current BPM. Recomputes if BPM changes.
−12 · −24 · BKWL	Loop wrap fade slope — soft, harder, brick-wall.
NUDGE slider	Translate the loop region left/right. Release to commit.
Double-click waveform	Set LOOP anchor at clicked position.
Ctrl+scroll waveform	Zoom in / out on the sample.

INPUT preamp

Control	Action
INPUT knob	Dry/wet preamp blend. LED meters input level.
Comp LED (under INPUT)	Cycle voice: amber = VINTAGE, red = FET, cyan = OPTO.

SPEED

Control	Action
SPEED knob	Varispeed 0.5×..2×. Slowing adds tape-style bit-crush + sample-rate reduction.
TAPE knob	Wet/dry tape saturation.
Tape LED (under TAPE)	Cycle machine: orange = SAT, green = WOW (modulation), magenta = LO-FI (bit-crush).

JUICE effect knobs (drag the top icon to reorder the chain)

Knob	Companion buttons
FILTER (LP/HP DJ sweep)	Q (LO/MD/HI) · RATE (OFF/1/2..1/128 LFO) · RANGE (SM/MD/LG)
GHOST (filtered feedback delay)	1/16 / 1/8 / 1/4 delay time
HAZE (reverb)	snowflake FREEZE · preset cycle (VAULT/CHROME/NEST/MIST/ABYSS/AURA)

Slots

Control	Action
Click slot 1–8	Save current loop region (with all effect state) or load if filled.
Right-click slot	Clear.
Number keys 1–8	Load only (won't accidentally overwrite).

MIDI sampler

Control	Action
MIDI Note-On	Plays the loaded sample at a pitch-shifted rate (C4 = note 60 = root).
Polyphony	8 voices, oldest-voice steal.
Co-exists with PLAY	Perform live MIDI on top of a running PLAY-button loop.

On-screen keyboard

Toggle the ♪ KEYS pill above the transport row to show / hide the bottom keyboard strip.

Control	Action
Click the keys	Play notes via mouse.
PITCH wheel (left of keyboard)	±12 semitones. Snaps back to centre on release.
MOD wheel (right of keyboard)	When ARP off → tremolo depth (5 Hz). When ARP on → arp rate selector (1/4 · 1/8 · 1/16 · 1/32 in four zones).
a w s e d f t g y h u j k o l	Computer-keyboard note input. a = base C (default C4).
z	Octave down.
x	Octave up.

Arpeggiator

On the keyboard strip:

Control	Action
ARP pill	Toggle arp engine. Held notes cycle at BPM-synced rate.
PATTERN pill	Cycle UP / DN / UPDN / RND.
MOD wheel	Selects rate while ARP is on.

LO-FI master mode

Control	Action
LO-FI pill (under SP-L)	Engage warm tanh saturation + 5-bit crush + 7 kHz HF rolloff on the final mix. Chassis re-skins pink/purple with animated film grain.
LO-FI knob (under the pill)	Dry/wet. Default 80% → 40% wet. Max 100% → 50% wet. Double-click → 80%.

Folder browse (corner of OLED)

• ◫ pick a folder; − / + step through audio files in it.

Easter eggs

• Double-click SP-L logo → randomize the accent color theme. State preserved across slots.

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Build

Requires CMake 3.22+ and a C++17 toolchain (Visual Studio 2022 on Windows, Xcode on macOS, GCC/Clang on Linux). JUCE 8.0.4 is pulled in via FetchContent.

cmake -S . -B build
cmake --build build --config Release

Build artefacts land under build/SPOOL_artefacts/Release/:

• Standalone/SPOOL.exe — runs as a desktop app
• VST3/SPOOL.vst3/ — drop into your DAW's VST3 folder
• (on macOS) AU/SPOOL.component

Just the standalone or just the VST3

cmake --build build --config Release --target SPOOL_Standalone
cmake --build build --config Release --target SPOOL_VST3

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Theming (optional)

SPOOL paints over the silver chassis with an optional background image. To add one, drop a bg.jpg, bg.png, background.jpg, or background.png into any of these:

1. <cwd>/assets/ — the working directory's assets folder (default in repo)
2. %APPDATA%/SPOOL/assets/ on Windows / ~/Library/Application Support/SPOOL/assets/ on macOS / ~/.config/SPOOL/assets/ on Linux
3. <plugin install dir>/assets/

First match wins. No image = blank silver panel.

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Logs

Diagnostic logs land in:

• Windows: %APPDATA%\SPOOL\spool.log
• macOS: ~/Library/Application Support/SPOOL/spool.log
• Linux: ~/.config/SPOOL/spool.log

Cleared each launch. Useful when reporting crashes.

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Support / bug reports

Found a bug or want to suggest a feature?

• Email: elliottdevs@gmail.com — pre-filled subject so it lands in the right pile. Please include your SPOOL version (shown in the standalone Options → menu, or hover the version line in About / Credits), OS, DAW (if applicable), what happened, and steps to reproduce.
• GitHub Issues: github.com/itselliott/spool/issues — great for anything reproducible.
• In-plugin shortcut: standalone → Options menu → Report a Bug → opens your default mail client with the version + OS template already filled out.

Support development

SPOOL is free forever. If it earned a spot in your toolbox, optional tips keep the lights on:

• Tip on Ko-fi — one-off or recurring, 0% fee on direct tips.
• GitHub Sponsors — monthly or one-off, GitHub takes 0%.

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License

SPOOL is built on JUCE 8, pulled in via CMake FetchContent under JUCE's GPLv3 terms. The SPOOL source code itself is provided as-is; redistribution must comply with JUCE's licensing — see juce.com/get-juce/ for commercial licensing if you intend to ship binaries non-GPL.