FM1 DRUM OS

A drum-focused sampler and sequencer for the M-VAVE FM-1. FM1 DRUM OS turns the FM-1 into a compact, hands-on drum machine built around sampling, unquantized playing, expressive sequencing and sound shaping. Make a beat on the hardware, adjust individual drum lanes, or use the browser editor to manage kits, patterns and your own samples.

Web Editor · Download firmware · Firmware update guide · Report an issue

Current release: v1.0.0 — Initial Release.

Project saving, custom sample uploads and playback have been tested on physical M-VAVE FM-1 hardware. Back up your projects and user samples before updating.

Features

• 8 drum lanes with independent sample assignments, level, pan and mute.
• 6 simultaneous sample voices using the embedded sample engine.
• 55 built-in drum samples across kicks, snares, hats, open hats and percussion.
• 16 user sample slots for custom sounds, with upload and backup through the Web Editor.
• Up to 64 sequencer steps with swing, microtiming, adjustable quantization strength and ratchets.
• Live recording with overdub/replace, optional count-in and metronome.
• Per-pad sound editing including tune, start, end and decay.
• 8 lane effects and 6 master effects for shaping individual hits and the drum bus.
• 6 factory kits, 4 user kits and 4 project slots.
• Autosave and project recovery so you can pick up where you left off.
• USB MIDI / SysEx integration with a browser-based editor.

The emphasis is on playing rather than programming: record loosely, tighten the groove only as much as you want, and make the drums your own.

Web Editor

Open FM1 DRUM OS Web Editor

The editor runs in a compatible desktop browser and lets you:

• Edit kits, pads, patterns, effects and projects.
• Import WAV files, convert them to mono IMA ADPCM and fit them into a user sample slot.
• Preview sounds before sending them to the FM-1.
• Upload custom samples to the 16 user slots and assign them to pads.
• Export and import sample-library backups.
• Work offline, then connect to the device over USB MIDI when ready.

Use Chrome or Edge with a USB data cable. Web MIDI with SysEx permission is required for device communication. The first connection requires browser permission; later sessions can reconnect automatically if permission is retained.

Sample limit: each new user-sample upload supports up to 19,968 bytes of IMA ADPCM (roughly 1.81 seconds at 22.05 kHz). The editor can trim or resample longer WAV files to fit. Older large-format samples and protected data may have additional compatibility restrictions.

Getting started

1. Back up your data. Export projects and the user sample library with the Web Editor before changing firmware.
2. Get the firmware. Download the .fwsc file for your device from Releases.
3. Update the FM-1. Follow the firmware update guide and use the updater appropriate for your hardware. Do not assume an update is reversible without a matching backup.
4. Make a beat. Pick a kit, play the pads and record a pattern. Use swing and quantization strength to shape the timing.
5. Add your own sounds. Open the Web Editor, import a WAV, choose Auto-fit, preview it and upload it to a free USER slot.

Sequencing and sound

FM1 DRUM OS is designed for drum programming and live performance rather than general-purpose synthesis. Each of the eight lanes can use any available sample, including the same source on multiple pads. The sequencer supports both intentionally loose timing and grid-based patterns, with per-step adjustments and effects to add movement and character.

The included factory kits provide starting points, not fixed instruments: change sample assignments or create your own kits in the editor.

Compatibility and important notes

• Hardware: M-VAVE FM-1, compatible with firmware package identity FM-1_900.
• Editor: a desktop browser with Web MIDI SysEx support; HTTPS is provided by GitHub Pages.
• Storage: 16 logical user-sample slots share four physical flash banks. Existing legacy samples can occupy multiple logical slots; protected or unknown data is not overwritten automatically.
• Projects: newer projects that reference USER sample IDs 59–70 may not work correctly on older firmware. Always make backups before downgrading.
• Saving: a runtime acknowledgement is not the same as a completed flash save. Confirm the device reports SAVED before switching it off.
• Audio preview: browser playback previews the sample data, not the complete hardware effects/output path.

See Compatibility & known limits for details.

Documentation

• Firmware update
• Web Editor
• Compatibility and known limits
• Build from source
• Third-party notices

Build from source

The firmware source and the Web Editor live in the same repository. Firmware builds require the separately obtained JieLi AC79 toolchain and matching SDK; they are not included here. The Web Editor is a TypeScript/Vite project.

cd drum-os-editor
npm ci
npm run build

For native firmware build requirements and tests, see BUILD.md.

Credits and license

FM1 DRUM OS is an independent, drum-focused adaptation of SLOOP and the Felucca firmware work by Leo Kuroshita / Hügelton Instruments. Thanks to the upstream developers and the wider FM-1 community.

Firmware/editor source is distributed under GPL-3.0-only. Third-party components, fonts and embedded audio have their own notices and permissions; see THIRD_PARTY_NOTICES.md.

This is an independent community firmware project and is not an official M-VAVE product.