Fonyx

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Spotify in your headphones, Discord on the speakers, the game on both with its own EQ, and a browser tab that ducks everything when it talks. Fonyx puts each application's audio into a group: a real PipeWire bus with its own fader, its own processing chain and as many outputs as you like.

A background daemon owns the audio graph and does all the processing, so nothing stops when you close the window. The desktop app, the fonyx CLI and the Quickshell surfaces are all thin clients over one D-Bus interface.

🧪 Status: public beta

Fonyx is new, and in public beta. Its features are in daily use on Arch Linux and checked by automatic tests on Ubuntu 24.04, but it hasn't met many other systems yet. Try it, and tell us how it works on yours:

• Report a bug: your distribution, how you installed Fonyx, and what you saw.
• Request a feature
• Release notes

Reproducible bug reports are the most useful feedback there is.

⚡ Quick start

From source, as systemd user services with a watchdog (no root):

git clone https://github.com/ArdenDiago/Fonyx.git && cd Fonyx
sh packaging/install-user.sh

As an AppImage, to try it without installing anything: download Fonyx-x86_64.AppImage, then:

chmod +x Fonyx-x86_64.AppImage
./Fonyx-x86_64.AppImage

It starts its own audio engine and stops it when you close the window. It needs PipeWire with WirePlumber on a recent distribution (Debian 12, Ubuntu 23.04, Fedora 37, Arch, or newer).

From the Snap Store: coming soon. A one-line snap install fonyx is on its way. Until then, use the AppImage or build from source.

Then drive it from the window, or from a terminal:

fonyx group create Music
fonyx input move spotify Music
fonyx fader set Music -6dB
fonyx system status

• A Linux session running PipeWire, with WirePlumber's wpctl
• Rust with Cargo, clang (for pipewire-rs bindings) and webkit2gtk-4.1 (Tauri's webview)
• Optional: quickshell for the shell surfaces, Node.js for the UI tests

pacman -S clang webkit2gtk-4.1     # Arch Linux

cargo build --workspace            # daemon, UI and CLI
cargo test --workspace             # unit tests, no PipeWire needed
cargo run -p fonyx-daemon          # RUST_LOG=info for stream and group logging
cargo run -p fonyx-ui              # in a second terminal

The UI connects to the daemon at startup, so start the daemon first. Developed on Arch Linux; CI builds and tests on Ubuntu 24.04. Install details are in Packaging, every command in Command line.

🎛 A look inside

Captured in a throwaway PipeWire session with four demo streams playing.

🔥 What it does

Routing

• Every app lands in a protected Default group, so nothing bypasses the mixer

• Send a group to several outputs at once, each with its own gain, switch and delay compensation

• Master bus: the sum of every group, routable on its own

• Cue bus: solo an app into your headphones while the rest ducks there

• Own DSP: give one app its own group, cloned from where it was

• Per-stream left / right / stereo isolate

Sound, per group

• Gain under a master fader

• High-pass and low-pass filters

• Six-band parametric EQ with a whole-curve level offset

• Compressor and gate

• Plugins: Soft Clipper, Stereo Widener, Deep Bass, Mids

• Mono/stereo, pan, and an always-on safety limiter

• Every parameter smoothed. Nothing clicks, nothing snaps

Automation

• Scenes: capture and recall the whole mixer

• Profiles: an app returns to its group and volume when it restarts

• Rules: react to app start/stop, device plug/unplug, scenes, resume from sleep

• Ducking: lower chosen groups while another one is active

Tools

• Record a group's processed signal to WAV or FLAC

• Doctor: health checks for groups, buffer, underruns and outputs

• Signal-flow graph from streams through groups to outputs

• Live meters, spectrum, gain reduction, CPU and RAM

Three ways in

• Desktop app (Tauri): ten tabs, a draggable EQ graph, a live compressor curve, keyboard control, light and dark themes

• fonyx CLI: every mixer function by name, prefix or alias, with --json for scripts

• Quickshell: a standalone app, a status-bar fader widget and a keybind popup

Built for Linux

• PipeWire for every byte of audio

• One D-Bus session service: org.fonyx.Daemon

• systemd user services with a watchdog

• Config in plain TOML at ~/.config/fonyx/

• Close or crash any window; the audio keeps playing

🧭 How it works

Each group is a virtual PipeWire sink: a filter node that apps are linked into port by port, running the DSP chain in its realtime callback. Its output is linked to one small route node per output (gain, delay), and those to the devices. It is all one PipeWire graph cycle, so Fonyx adds no latency of its own.

Area	Technology
Daemon and DSP	Rust, PipeWire via pipewire-rs
IPC	D-Bus session bus via zbus
Desktop app	Tauri 2, one HTML file, no framework, no build step
Shell integration	Quickshell (QML) through busctl
Packaging	Snap Store, user install script, systemd user units
Tests	Rust unit tests; Playwright endpoint and UI tests against a real daemon

Solid arrows are calls or data flow at run time; dotted arrows show what the config file stores.

This is the beginning of the README. Read the rest at the original. Read the full README ↗