Notation follows the Percussive Arts Society standard: cymbals are x noteheads, drums are round; bass drum sits in the first space, snare in the third, toms above it, ride on the top line, hi-hat above the staff, crash on the ledger line, foot hi-hat below the staff. o = open hi-hat, + = closed, > = accent, ( ) = ghost note, R/L = sticking. Counts read 1 e & a.
Last run
Pattern editor
Sixteenth-note grid in 4/4, up to eight bars. Click a cell for a note, again for an accent (>), again for a ghost note ( ), again to clear. Type R or L in the sticking row. Saved patterns appear under "My patterns" in the pattern list and live in this browser; Export writes them to a file you can import elsewhere.
Pad map
Click a pad, then hit it on the kit to learn its MIDI note. Defaults are the Alesis Nitro factory map. Hi-hat open vs closed: if the module sends different note numbers (46 open, 42 closed), those are used. If it sends one note for both, learn both "Hi-hat (closed)" and "Hi-hat (open)" to that same note and the pedal position (controller 4) decides instead: pressed = closed.
No kit handy? Keyboard: space bass drum, J snare, F closed hi-hat, G open hi-hat, D foot hi-hat, R high tom, T mid tom, Y floor tom, U crash, I ride.
"Play pattern" performs the pattern at the chosen tempo. Pick the module under Playback sound to hear it on the kit's own sounds (the page sends it MIDI), or leave Built-in sounds. "Metronome" is the click alone at that tempo, accented on beat 1, for the bar count or until Stop; Click volume applies to every mode, and at zero you practise without a click.
If the beat flash and the click do not land together, run the Metronome and adjust Visual offset until they do: raise it when the flash comes first (usual with Bluetooth headphones or speakers), lower it when the click comes first. It only moves the display; scoring is unaffected. The status line shows the latency the browser reports.
Free and open source (MIT). Everything stays in this browser; nothing is sent anywhere. Source on GitHub.