Step sequencers are foundational tools in electronic music — from the Roland TR-808 that defined hip-hop to modern DAWs. But most web-based sequencers either require audio samples (increasing page load) or are overly complex. BeatPulse was built to be an instant, sample-free drum machine that runs entirely in the browser using synthesized sounds.
A 16-step sequencer with 8 synthesized percussion tracks. Every sound is generated in real-time using the Web Audio API — no samples, no downloads. Features include swing timing, per-track muting, 4 pattern slots, preset patterns, and adjustable master volume.
Each drum sound is synthesized from basic audio primitives:
The sequencer uses a lookahead scheduler that checks 25ms ahead and queues notes using AudioContext.currentTime for sample-accurate timing. Swing is implemented by delaying even-numbered steps based on the swing percentage.