spectral

A real-time audio noise suppression application

repo ↗

rust · nix

Spectral strips background noise out of your microphone in real time, powered by RNNoise — a hybrid DSP and neural-network suppression model from Xiph.org. On Linux it registers a native PipeWire virtual microphone, so any application can pick the cleaned signal as its input.

Why

Fans, keyboards, and street noise leak into every call and recording, and the suppressors that handle them well tend to be proprietary and cloud-bound. Spectral does it locally: one virtual mic any app can select, with the denoising, a voice-activity gate, and optional rumble and leveling all under your control.

Design

Rust — real-time audio can’t tolerate a garbage-collector pause on the hot path, and memory safety matters across the PipeWire FFI boundary, where panic = "unwind" is kept deliberately so a failed C call or a poisoned lock unwinds instead of aborting. Denoising is a pure-Rust RNNoise port. The app splits in two: a thin Slint GUI that doubles as a headless CLI, and a background spectral-daemon that owns all audio processing — they talk over a Unix-domain socket. A platform/linux/ seam leaves room for other backends later.

Try it

nix run git+https://codeberg.org/mmc/spectral

Launch spectral, pick your input device, and click Enable — the daemon starts on its own and a virtual mic named Spectral-Mic appears for any app to select. The same binary works headless (spectral enable --device <id>, spectral status, spectral disable).

Nix is the supported install path — it brings the PipeWire and WirePlumber configuration Spectral depends on; an AUR package (spectral-mic) is pending. Spectral needs a running PipeWire session.