Compose Guide: Free Online Beat Maker, Synthesizer, & Sequencer

Compose is Crayonbrain's in-browser music sketchpad. You can program drums on a step sequencer, write melodies and chords on a piano roll, design sounds on a built-in synthesizer, mix levels, preview reactive visuals, and export your idea as WAV audio or MIDI to finish in a DAW like FL Studio.

You do not need to install anything. Open Compose from the tab bar or the menu, and start clicking steps. An account is optional for experimenting; sign in when you want to sign in to save projects to the cloud or post to the community Browse feed.

Transport controls live in the top navbar while you are on Compose (and on Visuals when you are previewing an uploaded file). See also Export WAV and MIDI.

• Play / Stop: starts or stops the whole sequence (drums, keys, and any active instruments together).
• Back to start: jumps playback to the beginning of the loop.
• Tempo (BPM): tap the tempo control in the navbar to expand the slider. Drag to change speed; the sequencer, piano roll, and exports all follow the current BPM.
• Export: the download button opens export options (covered below). It is available on Compose and on Visuals when you are in Upload mode with a loaded file.

At the top of the sequencer area, use the Drums / Keys toggle to switch views. In Drums mode you get a classic grid: each row is a drum sound, each column is a step in the pattern.

• Toggle steps: click a cell to turn a hit on or off. Active steps highlight so you can read the groove at a glance.
• Bar lines: steps are grouped by bar. The pattern length grows when you add bars (see Song length).
• Solo: hear only the drum grid while you edit, without melody layers fighting for attention.
• Clear: wipe the current drum pattern (use undo if you change your mind).
• Undo: step back through recent drum edits.
• Jump to start: move the playhead to step one without stopping transport.
• Drum list: open the drum drawer to add or remove rows (kicks, snares, hats, 808s, and more). Only drums you add appear in the grid.
• Mixer: open the mixer from the drum toolbar to balance drum and instrument levels (see Mixer).

For step-by-step patterns (house, trap, hip-hop, breakbeat, lo-fi), see the Drum patterns guide. Genre quick starts open Compose with a pre-filled pattern: beat maker, drum pad, 808 sequencer, techno, and house.

Switch the toggle to Keys to open the piano roll. Pitch runs vertically; time runs horizontally across the same bar length as your drums. For chord shapes, pad voicings, pluck arps, and basslines, see the Piano roll guide.

• Add notes: click on the grid to place notes. Drag or adjust length where supported for longer hits.
• Instrument: tap the instrument name to open the drawer. Choose built-in samples (pads, plucks, leads, bass) or presets you have saved.
• Solo: audition only the current instrument's part.
• Synthesizer: jump to the full synth editor for custom timbres (see Synthesizer).
• Clear / Undo: same workflow as drums, scoped to the piano roll.
• Mixer: shared with drums; use it to set relative volumes before export.

Each instrument has its own lane in the project data. Switch instruments from the drawer to build basslines, chords, and leads in layers, then play everything back together.

From the piano roll toolbar, tap Synthesizer to enter synth mode. Crayonbrain runs a three-oscillator synth: each of Osc 1–3 can be enabled with its own waveform, filter, ADSR envelope, and LFO. For how subtractive synthesis works and patch-building tips, see the Synthesizer guide.

• Presets drawer: on the right, browse default and user-saved synth presets. Apply, save, load, or clear patches.
• Back to Composer: return to the piano roll without losing synth settings.
• Visualizer strip: in synth view, a collapsible reactive visual can sit above the panel (see Built-in visualizer). Use the navbar control to show or hide it while you tweak sound design.
• Navbar presets: when the synth view is active, the navbar may expose quick preset actions (open drawer, save, load) instead of the usual mix transport row.

Synth notes can be exported as audio alongside sampled instruments when you run a WAV export that includes the synth track.

Open Mixer from the drum or piano roll toolbar. You get per-drum and per-instrument level sliders plus a limiter threshold to tame peaks before export.

When you are done balancing, confirm to return to the sequencer. Mix settings stay with the project for playback and export.

Below the sequencer (in drums or keys mode, not inside the synth editor), you can enable Visualizer. This drives graphics from your mix in real time.

• Butterchurn: open-source web port of the famous Milkdrop visualizer featured in Winamp.
• Spectrum: frequency bars tied to the master output.
• Melody Roll: stream of notes. Customize note and background colors and filter which instruments drive the display.
• Starweaver: mathematical-based starfield visualizer with extra controls for shape and audio influence.

For dedicated visual workflows (mic input, upload, fullscreen, video file export), use the Visuals guide and the Visuals tab.

The File menu at the top of Compose handles project lifecycle.

• New: start a fresh project. You will be prompted if you have unsaved work.
• Save: requires sign-in. Name your project; data includes drums, piano roll lanes, BPM, bars, mix levels, and related settings.
• Load: open a saved project from your Profile library.

The current project title appears under the File menu so you always know what you are editing. Guest users can still play and export in the session, but cloud save needs a free account.

Tap Post to share your loop to the public Browse feed. If the project is not saved yet, Compose will walk you through saving first.

Posted versions are shared under Creative Commons terms described in the Terms. Others can preview and remix your post into their own Compose session.

Under the project title, use − and + to remove or add bars. The drum grid and piano roll both expand or contract to match. You cannot remove the last bar or change length while tracks are playing.

Use the navbar export control on Compose. The modal lets you choose:

• WAV: renders a stereo bounce of selected drums and instruments for the current bar length and BPM. Pick which tracks to include via the checklist.
• MIDI: downloads a standard MIDI file with drum and note data so you can continue in FL Studio, Ableton, or another DAW.

Estimated file size and duration are shown before you confirm. WAV export runs offline in the browser from your pattern data, no upload of the rendered audio to our servers for that step. To turn a bounce into a social clip, export WAV here then follow the Visuals guide on the Visuals tab.

On the Browse tab, play community posts and hit Remix to load a track into Compose. If you already have patterns, Confirm before replacing. Remix is the fastest way to get started with a new idea. You can also open Browse from the home page SEO link to jump straight to the feed.