Beat Sequencer Online

A free browser drum machine — program a step pattern, hit play, and download the loop as a WAV file. No account, no install, no server.

BPM

120

Volume

80%

Steps

Tracks

Stopped

Pattern:

How it works

The sequencer divides each bar into equal time slices called steps. At each step, any active track fires its drum sound. The timing engine uses the Web Audio API — specifically a lookahead scheduler — to queue sounds ahead of the clock by a small buffer (~25 ms), so playback stays perfectly in time regardless of browser repaint lag.

Step grid Click any cell to toggle it on (coloured) or off. Each row is one drum voice. Each column is one time step in the bar.

Synthesized drums All sounds are generated with Web Audio API — no sample files. Kick = pitched sine with fast pitch drop. Snare = noise burst + resonant tone. Hi-hat = filtered white noise.

BPM & steps Step duration = 60 / BPM / 4 seconds (16th-note grid). At 120 BPM a 16-step loop lasts 2 seconds. Changing BPM takes effect on the next step.

WAV export Clicking "Export WAV" renders the entire loop offline via OfflineAudioContext at 44 100 Hz stereo, then encodes the PCM data into a standard 16-bit WAV file and triggers a browser download — no server involved.

Step duration formula: stepSec = 60 / bpm / 4. For 16 steps at 120 BPM: 60/120/4 = 0.125 s per step → loop = 2.0 s.

Frequently asked questions

What is a beat sequencer / step sequencer?: A step sequencer is a tool that divides a repeating loop into equal time slots (steps). Each row represents one instrument voice (drum track) and each column is one time step. When a cell is active, the drum fires at that moment. Chaining steps creates a rhythmic pattern. It is the foundational interface used in classic hardware drum machines like the Roland TR-808 and TR-909, and is now ubiquitous in digital audio workstations (DAWs).
Do I need to install anything or sign up?: No. Everything runs inside your browser using the Web Audio API, which is built into all modern browsers (Chrome, Firefox, Safari, Edge). No plugins, no Flash, no account. The WAV file is assembled in JavaScript and downloaded directly — your pattern data never leaves your device.
How does the WAV export work, and can I use it in my DAW?: Clicking "Export WAV" triggers an OfflineAudioContext that renders every step of the loop at CD quality (44 100 Hz, 16-bit stereo). The raw PCM samples are then packed into a standard WAV container and downloaded as a file. The resulting file is a plain 44.1 kHz stereo WAV — compatible with every DAW (Ableton, Logic Pro, FL Studio, GarageBand, Reaper, and others) as a loop or one-shot sample. You can import it, time-stretch it, or layer it with other tracks.
How do I change the tempo or time signature?: Drag the BPM slider (40–240 BPM) to set the tempo. The step count selector (8, 12, or 16 steps) changes the loop length: 8 steps gives a half-bar loop; 16 steps gives a full bar (4/4 feel). For a 3/4 or 6/8 feel, use 12 steps — each beat group of 3 creates three even subdivisions. Tempo changes take effect immediately on the next scheduled step.
What are the synthesized drum sounds?: All sounds are synthesised in real time using the Web Audio API — there are no audio sample files to download. The Kick uses a sine oscillator with an exponential pitch drop from ~180 Hz to ~40 Hz over 0.5 s (the classic "thump"). The Snare mixes a short noise burst through a bandpass filter with a secondary resonant sine for the "crack". The Hi-Hat is white noise through a sharp high-pass filter. The Open Hat is the same but with a longer decay. The Clap is noise shaped with a slight multi-tap delay to mimic hand clap. The Cowbell uses two square-wave oscillators slightly detuned, through a short bandpass envelope.