Make it squelch.
ACID FM1 is an independent acid instrument for the M-VAVE FM-1. The studio uses the same original C engine as the firmware. The hardware emulator also runs the actual panel and LCD code. It is inspired by classic acid synthesis and Acid V’s public feature set; it contains no Arturia code, sounds, graphics, or presets.
Start in the browser
- Open the studio and click Start sequence. Begin with a modest output volume.
- Move Cutoff and Resonance. Envelope changes how far the filter opens on each note; Decay changes how quickly it closes. Accent raises selected steps; Slide controls the pitch transition into the next tied note.
- Edit notes as semitone offsets from the root. Gate is on/off, amber is accent, blue is slide. Select a step number to edit probability, ratchets, and a cutoff lock. Negative cutoff-lock values mean off.
- Try independent note, accent, and slide lengths for polymetric patterns. Bank buttons access all 64 steps. Only steps within Length play.
- Use Modulation to route three independent sources. Custom curve mode interpolates eight points. Effects includes seven original distortions and compact delay, chorus, and ambience.
Drag knobs vertically; hold Shift for fine changes. Arrow keys work and double-click restores the default. Live mode plays the mono voice directly; the arpeggiator needs held notes and running transport. In sequencer mode, the keys transpose the root.
Keep your work
Save and Recall use four local browser slots. Export a JSON patch for a durable backup. Import checks dimensions and values before changing state. Generate and Mutate retain one undo state. No application telemetry, accounts, external fonts, or analytics are used. GitHub hosting and a browser/OS MIDI or speech service have their own behavior.
Studio patches and hardware slots are separate. There is no studio-to-device patch-transfer protocol in this version. The hardware-view emulator uses separate simulated storage and edits the actual firmware interface.
MIDI and audio export
Connect MIDI input asks permission only when clicked. Chrome and Edge generally support Web MIDI; other browsers vary. Use Circuit → Clock to follow incoming 24-PPQN MIDI clock; start/continue/stop are supported. If clock disappears for two seconds, the voice releases. All MIDI channels are accepted.
CC 1 vibrato depth, 7 volume, 71 resonance, 74 cutoff, 75 decay, 76 envelope, 77 accent, 78 drive, 91 ambience, 93 delay. Pitch bend maps ±2 semitones into Tune. CC 120 panics; CC 123 releases all notes.
WAV bounce renders two pattern cycles at 44.1 kHz plus one second of effects tail, using the same C engine offline. MIDI export writes one pattern cycle with note velocities, gates, swing and overlaps. It cannot carry this instrument’s filter sound or make another synth interpret overlaps as slide. Live/arp audio bounce is not provided.
Physical panel
SELECT moves between pages; on the Sequencer page it selects steps. K1–K4 change the four displayed values. PRESET loads one of eight factory patches and stops playback. PLAY starts/stops. HOME + PLAY panics. OCT−/OCT+ shift the keys.
| BUTTON | FUNCTION |
|---|---|
| HOME | Voice page; hold as a modifier |
| ENV | Decay / accent / slide / gate |
| FX | Cycle effects, distortion, space |
| LFO | Cycle modulators 1–3; ALGO chooses destination |
| SEQ | Step editor / pattern settings |
| GLO | Clock / utility settings |
| EDIT | Open step editor |
| SEL | Cycle scale |
| ARP | Sequencer / arpeggiator |
| REC | Toggle step-note recording |
| SAVE | Save current hardware slot |
| HOME + SAVE | Recall current slot |
| HOME + ALGO | Select slot 1–4; slot 1 loads at boot |
On the step page, K1–K4 edit note, gate, accent, slide. Hold HOME for probability, ratchet, cutoff lock, and clear lock. The LCD and page list expose the remaining circuit, modulation routing, pattern, and performance settings. See the complete mapping.
Experimental firmware
Not yet tested on a physical FM1. Compilation, native tests, and browser tests do not validate real-time headroom, the codec, or recovery. Back up existing projects and patches, and confirm your recovery method before considering a flash. This version can overwrite the storage used by other firmwares.
Download the experimental release and checksums ↗
The release includes the installable .fwsc, raw app, source and license notices. Use the update method supported by your current firmware. This site does not flash a device automatically. The command-line installer comes from the pinned fm1-base platform.
python3 base/tools/fm1_install.py acid-fm1-0.1.0.fwsc
Recovery references: FM-1-transporter and the official Workbench. Read the physical acceptance checklist and build instructions before use.
Scope and sound
The filter is an original saturated four-pole approximation, not Arturia’s circuit model. Effects are compact adaptations for this hardware, not the full desktop rack. The delay buffer holds roughly 743 ms at 44.1 kHz; long divisions at slow tempos clamp to the available length. Oversampling covers the voice, not the whole effect chain. No sonic equivalence to Acid V is claimed.
Original app and DSP: AGPL-3.0-only. Platform: MPL-2.0. Fonts: OFL. SDK package data: Apache-2.0. Credits and provenance ↗