Loopbox is a 16-step, 9-track sequencer. Every sound is synthesised live in your browser —
there are no samples and nothing to load. Hit a demo button along the top to hear it,
then start changing things; you can't break anything that Reset won't fix.
1 · The grid
Each row is a track, each column is a 16th note. One pass through the grid is one bar.
- Click a cell to switch a note on or off, and drag across cells to paint several.
- Scroll on a lit cell to change it: on melodic tracks (Bass, Lead, Pad, Pluck)
that moves the pitch by a semitone and the cell shows the note name.
On drum tracks it changes velocity.
- Shift+scroll always changes velocity, on any track.
2 · Velocity and accents
Velocity is how hard a note is hit, shown as the length of the bar along the bottom of the
cell — full width is a hard accent, a stub is a ghost note. It does more than change
volume — soft hi-hats close up faster, hard bass and pluck notes open the filter further,
and ghost snares lose their tail. Alternating loud and soft hits is most of what makes a
pattern feel human rather than mechanical.
Try it: take the plain 16th hi-hat line in Acid Trip and scroll every
other cell down a few notches. The loop stops marching and starts grooving.
3 · Tracks and mixing
On each row label: M mutes, S solos (solo on any track silences all
un-soloed ones; mute still wins on its own track), and the small slider sets that
track's level. Clicking a track name focuses it — the focused row gets a blue
outline and is what your keyboard plays.
4 · Patterns and song mode
There are four pattern slots, A–D, each holding a full 16-step grid.
- Click a slot to edit it. If music is playing, the switch is queued to the end of the
current bar so the change lands on the beat rather than mid-phrase.
- Shift+click a slot copies the current pattern into it — the fastest way to build a
variation: copy A to B, then change a few cells.
- A slot with a dimly outlined edge already contains notes; a blue underline marks the
pattern currently sounding.
- Song plays the chain in the text box instead of looping one pattern.
A A A B
means three bars of A then one of B — the classic three-bars-and-a-fill. Type any
order of A–D. In Song mode the grid stays on whatever pattern you selected, so you can
keep editing while the chain plays around you.
5 · Playing live and recording
Click a track name to focus it, then play the keyboard:
| a w s e d f t g y h u j k |
Plays one octave on the focused melodic track, laid out like piano keys — the letter row is the white notes, the row above is the black notes. |
| z / x | Shift the keyboard down / up an octave. |
| 1 – 9 | Fire any track instantly, whatever is focused. Good for auditioning drums. |
| r | Arm or disarm recording. |
With ● REC armed while the transport is running, everything you play is written into
the grid, snapped to the nearest 16th. Record disarms nothing on stop — press it again to
turn it off. To undo a bad take, just toggle the offending cells off.
6 · Sound and effects
The header sliders act on the whole mix. Filter is a lowpass sweep from 120 Hz up to
18 kHz — pulling it down and letting it back up over a few bars is the oldest trick in
dance music. Delay is tempo-synced to a dotted eighth, so it always stays in time when
you change the tempo. Reverb feeds a generated impulse response. Swing pushes
every off-beat 16th later, which is what gives Boom Bap its lope; it does nothing to
straight patterns with no off-beats.
Each track sends a fixed amount to delay and reverb — Lead and Pluck send plenty, drums
almost none — so the master knobs change the character of the mix, not just its wetness.
7 · Saving and exporting
- Your work autosaves to this browser continuously. Closing the tab is safe;
reopening restores exactly where you left off.
- Export .json writes a project file you can keep or share; Import .json loads
one back. Copy share URL puts the entire project into a link — anyone opening it
gets an independent copy. Reset all wipes the stored project and starts clean.
- Export .wav renders however many bars you ask for to a real 16-bit stereo audio
file. It follows Song mode if it's on, otherwise it repeats the current pattern, and it
renders faster than real time through the same signal path you're hearing — so the file
sounds exactly like the app. A few seconds of reverb tail are included at the end.
8 · Shortcuts
| Space | Play / stop |
| r | Arm / disarm record |
| z / x | Keyboard octave down / up |
| 1 – 9 | Trigger track 1–9 |
| ? | Open this guide |
| Esc | Close this guide |
| scroll on a cell | Pitch (melodic) or velocity (drums) |
| shift+scroll | Velocity, any track |
| shift+click a slot | Copy current pattern into that slot |
9 · A quick first loop
- Hit Clear for an empty grid, then put Kick on steps 1, 5, 9 and 13.
- Add Clap on 5 and 13, and Hi-Hat on every other step.
- Focus Bass, click a few cells, and scroll them to find notes you like.
- Shift+click slot B to copy it, add a fill to the last bar, turn on
Song, and you have an arrangement.
- Export .wav when you like it.