Fontelle

A lightweight, Linux-first digital audio workstation built around SoundFont-based sample playback. An SF2 file supplies defaults — loop points, envelopes, filtering, mapping, tuning — and every one of them is yours to override. Free and open source, by Fopull LLC.

Status: early access, and a working studio. There is a window you can write a whole piece in; there is still a great deal on the design's list. See Project status.

Installing

Grab the archive for your platform from the latest release.

• Linux (the platform this is built for): unpack the tarball and run ./install.sh. It puts fontelle in ~/.local/bin with a menu entry and an icon — nothing outside your home folder, no root. ./install.sh --uninstall takes it away again. The binary needs ALSA, D-Bus and lilv (for LV2 plugins) from your distribution — on Debian/Ubuntu sudo apt install liblilv-0-0, on Fedora and Arch the package is lilv; the installer says so if anything is missing.
• Windows / macOS: unpack and run fontelle. The binaries are unsigned for now, so expect the first-run warning (macOS: right-click → Open).

Fontelle checks for a newer release when it starts and offers to install it from its start menu — the download is verified against the release's published checksums before anything is replaced. The check can be turned off on the Settings tab.

Why

Every existing SoundFont player treats the file's internal parameters as authoritative. Fontelle inverts that: the SF2 supplies a starting point, and nothing about it is locked. See FONTELLE_TDD.md for the full design — product thesis, invariants, crate layout, milestones, and the open questions still to resolve.

Running it

fontelle                          # installed
cargo run --release -p fontelle-app   # from a checkout

That opens the start menu: your recent projects, New project, Open a project…, and whether there is a newer Fontelle. Pick one and you are in the studio — a channel rack, a soundfont browser, an arrangement, a piano roll and a mixer, over a real audio device. --no-menu skips the menu; --help lists the rest.

Your soundfonts live in a folder Fontelle scans, shown at the bottom of the browser. Open folder shows you that folder in your file manager, creating it if it is not there yet — drop your .sf2 files in and they appear. Change… picks a different folder (Ctrl+click to add one alongside rather than replace), and the choice is remembered. The default is ~/.local/share/fontelle/soundfonts; there is a command-line equivalent if you prefer:

cargo run --release -p fontelle-app -- --soundfonts /path/to/your/soundfonts

Then: pick a soundfont in the browser, pick a preset (a plain click puts it on the selected channel; Ctrl+click puts it on a new one), and draw.

Draw / delete a note	left mouse / right mouse
Draw one to length	drag out from an empty cell
Lengthen one	drag its right edge
Tools	P draw, B paint, E select, D delete
Snap	S cycles bar / beat / 1⁄8 / 1⁄16 / 1⁄32 / triplet / off
Off the grid, one axis	hold Alt, hold Shift
Select a region	the Select tool, or Ctrl+drag
Clipboard	Ctrl+C / X / V, Ctrl+B duplicate
Undo / redo / save	Ctrl+Z / Ctrl+Y / Ctrl+S
Play	Space
Scroll	wheel for pitch, Shift+wheel for time
Zoom, about the pointer	Ctrl+wheel for time, Ctrl+Shift+wheel for pitch
Find a soundfont	Ctrl+F, then type — it matches letters in order, so gus finds GeneralUser GS
Every shortcut	F1, or the ? on the start menu and the transport bar — click one there to change it

The command line is still there and does more than the window does — offline WAV bounces, MIDI file import, live MIDI in, recording a take. --play-sf2 <file> plays a demo phrase through a preset; add --window to open the same project in the editor, --open <project.fontelle> to reopen a saved one.

Project status

Early access. Everything below is built, tested and used; the design in FONTELLE_TDD.md goes further, and PROGRESS.md is the blunt, living account of where each part stands — read it before trusting this list.

Composing. An arrangement with lanes and clips (MIDI, audio, automation), looping, stretch and cut, fades, a blade, and prefabs; a piano roll with draw, paint, select and delete tools, snap down to 1/32 and triplets, a property lane, ghosts, an arpeggiator and legato joining; slides and pitch bends; full undo, autosave and backups; project bundles that reopen with their audio.

Sound. The SoundFont sampler with every parameter user-owned and automatable; Flopsynth, the built-in synthesiser, with a 338-preset bank; a physically-modelled drum machine; sampler channels from imported audio; live MIDI with hot-plug, MIDI recording, MIDI and FL Studio score import; audio import, recording with monitoring, an audio clip editor, and offline rendering to WAV.

Mixing. A mixer with sends, routing and a master bus with a brickwall limiter; insert chains with wet/dry and delay compensation; track presets; twelve built-in effects, each a family rather than one sound — Utility, EQ, Filter, Compressor (with sidechain), Gate, Distortion, Bitcrush, Soften, Chorus, Delay, Reverb and Tune, an autotune.

Plugins. CLAP and LV2 instruments and effects, with their own editor windows and their state in the project.

Not built. VST2/VST3 hosting (a bridge is designed, out of tree), plugin export, sample streaming (a soundfont is fully resident), and the later milestones of the design. Windows and macOS builds come off the same release workflow as Linux and are less exercised.

See docs/scaffolding-notes.md for the one structural decision made during scaffolding that isn't explicit in the TDD.

Building

Requires Rust 2024 edition (MSRV 1.88.0). On Linux you'll also need ALSA, lilv (LV2), D-Bus (for rtkit) and windowing/XKB development headers:

sudo apt install libasound2-dev libudev-dev libxkbcommon-dev libwayland-dev \
    libxcb1-dev libxcb-render0-dev libxcb-shape0-dev libxcb-xfixes0-dev \
    liblilv-dev libdbus-1-dev

cargo check --workspace

Releasing

One version number for the whole workspace, in the root Cargo.toml. Bump it, commit, then tag and push:

git tag v0.2.0 && git push origin v0.2.0

release.yml refuses a tag that does not match the version in the tree, builds the Linux, Windows and macOS archives, and publishes them with a SHA256SUMS — which is what the start menu's updater reads.

License

Dual-licensed under MIT or Apache-2.0, at your option.

The factory Grand Piano's recordings (assets/flopsynth/samples/grand/) are cut from the Salamander Grand Piano by Alexander Holm, published under CC BY 3.0 and assembled as a soundfont by the FreePats project; they stay under that licence, with that credit.

The factory kits' recordings (assets/flopsynth/samples/kit/) are Fontelle's own drum machine, cut hit by hit; assets/flopsynth/samples/kit/README.md says how.

"SoundFont" is a Creative/E-mu trademark and is used here only descriptively.