BeatState — Free Drum Machine & Rhythm Computer

BeatState is a free drum machine and rhythm computer that runs entirely in the browser. Design beats with a multi-oscillator synthesis engine or sample kits, sequence with parameter locks, euclidean rhythms, and polymeters — then sync to hardware via MIDI. No installation required. Built by bsidez.

Synthesis Engine

• Multi-oscillator architecture — sine, triangle, square, sawtooth with FM modulation
• 20 curated synthesis kits — 808, 909, CR-78, LinnDrum, Metallic, Industrial, and more
• Per-voice frequency overrides, noise filters, pitch sweeps, and saturation
• Sample kit support — load and trigger audio samples alongside synthesis
• Per-voice effects: filter, delay, reverb, distortion, bit crush
• 12-voice polyphony with individual volume, pan, and mute per voice

Step Sequencer

• Up to 256 steps per pattern with 32-step page view
• Per-step velocity, probability, ratchet, flam, and step conditions
• Parameter locks (p-locks) — automate any voice parameter per step
• Euclidean rhythm generator with pulse count and rotation
• Polymetric engine — independent length per voice for evolving polyrhythms
• Per-voice swing with global and individual swing controls
• Pattern tools: rotate, reverse, mirror, double density, halve density, randomize
• Accent track with configurable accent amount
• Triplet, quintuplet, sextuplet, and septuplet time divisions

Pattern Library

• 466 curated patterns across 37 genres — from book transcriptions and classic machines
• Genres include: Rock, Funk, Jazz, Hip-Hop, House, Techno, Afrobeat, Latin, Reggae, Drum & Bass, and more
• Pattern chain for song arrangement with sequential playback
• Copy, paste, and clear patterns with full undo/redo

Mixer & Performance

• 12-channel mixer with faders, pan, mute, and solo per voice
• Master volume with headphone output
• Note repeat for live performance fills
• Scatter effect for glitch and stutter patterns
• Sidechain compression with amount and release controls
• Fill and pre-fill step conditions for live variation

MIDI

• MIDI output via Web MIDI API — trigger external synths and drum machines
• MIDI input for step recording and real-time play
• Master clock output with MIDI clock sync (24 PPQN)
• Slave mode — sync to external clock from Elektron, Roland, MPC, or any MIDI master
• Per-voice MIDI channel and note assignment

Use Cases

Beat making, drum programming, live performance, hardware synth sequencing, music education, rhythm practice, pattern design, electronic music production, sample triggering, and generative rhythm exploration.

About

BeatState is created by bsidez (JP van Vliet). Free to use at beatstate.net. Part of the bsidez ecosystem including BioMidi (biofeedback synthesizer) and Loopstate (generative MIDI sequencer).