Beat Harbor is a step-sequencer beat maker: 8 synthesized drum voices, a bass and a lead, 8 patterns and a song chain.
Everything is generated in your browser — no sample packs to download, no limits, no ads, and it works offline.
How to
- Play: press the round Play button or Space. Pattern mode loops the selected pattern; Song mode plays the chain from the arranger.
- Program a beat: tap a pad to turn it on, tap again for an accent (louder, white dot), a third time to turn it off. Choose 16 or 32 steps.
- Shape the groove: set Tempo (60–200 BPM, or Tap), Swing (50% = straight, ~67% = triplet shuffle), and per-track volume, pan, Mute and Solo. On a phone, volume and pan live in the Track panel.
- Write bass and melody: tap the Bass or Lead name, then use the piano roll in the Track panel. Notes follow the Key and Scale you choose. Turn on Chords to make the Lead play triads.
- Use your own sounds: select a track, then drop a WAV/MP3/OGG on the Track panel (or Choose file). On Bass and Lead the sample is pitched to your notes. Back to synth restores the built-in sound.
- Build a song: fill patterns A–H, then add them to the Song arranger in order. Switch to Song mode (or press Play song). Loop off = stop at the end.
- Export: pick Pattern or Song and a number of loops, then Export WAV (44.1 kHz stereo mixdown) or Export MIDI (one track per instrument, drums on channel 10).
- Save and share: Save .json writes the whole project (samples included) to a file; Open .json brings it back. Link to this pattern makes a short link containing the current pattern and its tempo, kit, key and scale.
Tips & shortcuts
- Space play / stop · 1–8 select pattern A–H · ? open help · Esc close help
- In the grid, arrow keys move between pads and Enter cycles a pad.
- Knobs: drag up/down (hold Shift for fine control), use arrow keys when focused, double-click to reset.
- Selecting another pattern while playing switches at the end of the current bar (the slot blinks while queued).
- Switching from 16 to 32 steps copies each bar into the second half so your groove keeps sounding the same.
- Randomize is musical, not chaotic: kicks on the downbeat, snares on 2 and 4, bass locked to the key.
- Mute and Solo also apply to exports.
- Undo (or Ctrl+Z) reverts the last Clear, Randomize, Paste or track change.
- In Song mode the grid follows the playing pattern so you can watch the arrangement.
FAQ
- Where is my data?
- Only in this browser: your project autosaves to local storage and your imported samples are kept in the browser's IndexedDB. Clearing site data erases them, so use Save .json for backups.
- Does it work offline?
- Yes. It is a single file; once open (or saved to your device) it needs no connection at all.
- Is it really free?
- Yes — no account, no ads, no caps on patterns, samples or exports. If it helps you, an optional tip keeps it going.
- Limits?
- 8 patterns of up to 32 steps, 10 tracks, 128 chain slots. Very long samples make project files large. Shared links carry one pattern only (no custom samples). Timing is most accurate while the tab is visible; background tabs may stutter.
Privacy
Nothing you make leaves your device. There are no servers, trackers or analytics; sounds are synthesized and samples are decoded locally. A share link contains the pattern itself inside the link — nothing is uploaded.