Getting started
spool. puts a whole music studio on a single screen. There’s no menu-diving — everything is one tap away.
The four modes
Switch modes with the icons in the top bar (left rail in landscape):
| Mode | Icon | What it’s for |
|---|---|---|
| SYNTH | waveform | Play and design sounds with fourteen engines. |
| TAPE | tape reel | Record everything onto a 4-track tape. |
| MIXER | sliders | Balance the tracks, master effects, export. |
| PERFORM | hand | A live surface — tape moves, faders, and a double keyboard. |
Next to the mode icons you’ll find five utility buttons: the sequencer (grid — tap to open it, press and hold to switch it on or off), tempo (metronome icon), the browser (folder — an amber dot means unsaved changes), MIDI settings (piano icon), and About (ⓘ).
The four knobs
Every screen puts four color-coded knobs under the display — coral, amber, mint, periwinkle. They always control the four things currently shown above them, and they’re relabeled by whichever page you’re on.
- Drag up or down on a knob to turn it.
- While dragging, slide your finger sideways away from the knob for fine control — a FINE × readout shows how much finer you’re going.
- Time-based knobs can lock to the beat (a small metronome toggle appears on the knob); pitch knobs snap to semitones; pan and EQ knobs have a center detent.
The display is an instrument too
Each engine and effect has its own animated scene — and the scenes are touchable. Glowing hint dots mark grabbable elements; each dot is tinted to match one of the four knobs. Grab a dot and drag it to play that parameter directly in the scene.
Make your first sound
- Open SYNTH.
- Play the keyboard — you’ll hear the current sound and see the scene react.
- Turn the four knobs on the ENGINE page to shape the sound’s character.
- Tap ENV to shape how notes fade in and out (drag the envelope curve), and FX to add an effect. The LFO strip above the tabs adds movement.
Favorites
The eight colored chips along the top are favorite slots. Tap one to load that sound instantly — even while the tape rolls. Press and hold a slot for the menu: Save current sound here, Save as preset…, Load preset…, or Clear. A small amber dot on a slot means you’ve edited the sound since loading it.
The keyboard
- Play with as many fingers as you like — it’s a real multi-touch keyboard, and it senses how hard you press for velocity (on devices that support it).
- Resize grip (✥): drag it up or down to change the keyboard’s height, or sideways to change the key width — from chunky keys to a wide span. Your size sticks between sessions.
- Scroll grip (↔): drag to slide the keyboard along the full range, from the lowest A to the highest C. Give it a flick and it glides with momentum.
- HOLD: latches whatever is sounding — a note, a chord, or a running sequence — so it keeps playing hands-free.
- LIFT / DROP (boxed ↑ ↓ at the right end): spool.’s audio clipboard. LIFT grabs audio from wherever you are — a tape track, the sampler — and DROP pastes it somewhere else. Lift a tape section, drop it on a drum kit.
Transport
The transport lives at the left end of the keyboard row in every mode:
- ⏮ — back to the start.
- ▶ / ■ — play or stop.
- ● Record — tap to start recording right away, or press and hold to arm it (the button turns amber): recording then starts the instant you play your first note. While recording it glows red.
Tempo
Tap the metronome icon to open the tempo screen: a big BPM readout, a slider (40–240), a TAP TEMPO button, and a metronome toggle. The clock modes are FREE (tempo and tape speed independent) and BEAT (Beat Match — tempo and tape speed lock together, and bar markers appear on the tape).
Next: Synth & engines →