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orDrumbox - Free Online Drum Machine

orDrumbox is a browser-based beat maker and step sequencer. It provides a creative environment to build drum patterns using acoustic, vintage, and 8-bit kits without any software installation.

Core Features

Step Sequencer

  • Programmable grid for note entry and track looping
  • Support for complex polyrhythm and per-track swing settings
  • Precision controls for pitch, volume, and panning per note
  • Retrigger and Euclidean Fill with visual ghost notes (blue for retrigger, yellow for euclidian)
  • Real-time visual feedback with step-by-step playback

Synthesis & Automation

  • Integrated Soft Synth with 3 VCOs, ADSR envelope, and filters
  • AudioWorklet mode for low-latency synthesis when supported
  • LFO modulators for dynamic pitch and volume effects
  • Per-track effects: Reverb and Saturation

Audio & Export

  • High-quality WAV export for use in other DAWs
  • Real-time audio analysis and visualization
  • Multiple drumkits with authentic sounds

AI Generation

  • Automatic Bass Line Generator
  • Pattern Generator with style detection

MCP Server

  • Programmatic control via Model Context Protocol (MCP)
  • Create and modify patterns via JSON-RPC
  • Tools: createNewPattern, addExtendedNotesToPattern, addNotesToPattern, updateTrack, setPatternBpm, setPatternTags, and more
  • Access to instruments, samples, and pattern management

MIDI Support

  • Compatible with external MIDI controllers
  • General MIDI (GM) standard support

Getting Started

Choosing a Pattern and Drumkit

When you first launch orDrumbox, you can explore the built-in examples using the two dropdown menus located in the toolbar:

  • The KIT dropdown allows you to select different drumkits (e.g., Real, Electronic, Vintage). Each kit contains a collection of sounds like kick, snare, hi-hat, tom, and more.
  • The PTN dropdown lets you choose from preset patterns organized by music style (rock, jazz, electronic, etc.).

Select a drumkit and pattern combination, then press the PLAY button to hear the example. This helps you understand how different sounds and patterns work together.

Adding and Removing Notes

The main grid displays the step sequencer where you can create your own beats:

  • Add a note: Click on any empty cell in the grid to add a note at that step. The note will play when the sequencer reaches that position during playback.
  • Remove a note: Click on an existing note in the grid to remove it.
  • Play/Pause: Use the PLAY button in the toolbar to start or stop the sequencer.

Each column represents a beat step, and each row corresponds to a specific track (e.g., KICK, SNARE, HI-HAT). You can have multiple notes in the same row at different positions.

Probability Triggers

Each note can use probability triggers to create subtle random variations while the pattern keeps looping:

  • Trigger Probability controls the chance that the selected note will play after its normal trigger timing. 1 means always play, 0.5 means about half the time, and 0 means never play.
  • Arp Probability controls the chance that each individual arpeggio note will play. This lets an arpeggio keep its shape while some of its internal notes are randomly skipped.

Both probability controls use values from 0 to 1, where 1 equals 100%.

Modifying Settings with Sliders and Controls

Each track has adjustable parameters accessible through the track control panel. Use these controls to customize your sound:

  • Volume (velocity): Adjust the overall loudness of the track (0 to 1).
  • Pan (PANO): Move the sound left or right in the stereo field (-1 to 1).
  • Pitch: Change the pitch of the sound in semitones.
  • Swing: Add swing timing to give the groove a more laid-back feel.
  • Loop Step: Define where the track loops back in the pattern.
  • AUTO mode: Enable automatic track generation.

The toolbar also includes:

  • BPM: Set the tempo of the pattern (20 to 250 beats per minute).
  • Pattern Length: Adjust how many bars the pattern plays before looping.

You can also access additional controls by clicking the TOOLS button, which provides options for exporting audio (WAV), clearing the pattern, and more.

Direct Controls

Use your computer keyboard as a drum pad. Every key is mapped to a specific sound in the selected drumkit for live finger-drumming.

MIDI Controllers

For more professional setups, orDrumbox is compatible with external MIDI controllers. You can use any MIDI hardware following the General MIDI (GM) standard.

Data Management

  • Import and export patterns as local project files (JSON)
  • Save and load your creations

Technical Details

  • Framework: Vanilla JavaScript with ES6 modules
  • Build Tool: Vite
  • Audio: Web Audio API with AudioWorklet support
  • Node Pool: Recycling of GainNode, BiquadFilterNode, and StereoPannerNode for reduced GC pressure
  • Storage: LocalStorage for persistence, JSON for import/export
  • MCP Server: Standalone Node.js server for programmatic control

Global sound processing:

Compressor: threshold -12dB, ratio 4:1, attack 5ms, release 150ms HighPass: 35 Hz (removes unwanted low frequencies) LowPass: 18500 Hz (anti-aliasing) MasterGain: 4.0 (compensation for Web Audio loudness deficit)

Resources

License

orDrumbox is maintained by the community under the GPL V3 License.


Copyright 2026 OrDrumbox Team

About

A drum machine and sequencer and soft synth built with the Web Audio API. Vanilla JavaScript. No frameworks. No libraries

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