EKO

The native macOS player for your Navidrome, Subsonic and local library — a real Rust audio engine wrapped in a neumorphic interface, playing every track at its own sample rate, untouched. Bit-perfect, and it proves it.

What it does

• Native bit-perfect playback at the file's own sample rate (FLAC, ALAC, WAV, AIFF, MP3, AAC).
• Automatic device rate-switching — the OS output follows the music, no resampling.
• A live signal path with an honest bit-perfect seal.
• Real 10-band biquad EQ, software volume, a Rust FFT spectrum.
• Local files + Navidrome / Subsonic streaming through one engine.
• Output device picker, a mini player, light & dark themes.

Installation

Grab a release, or build from source (see Building).

# clone & install
$ git clone https://github.com/reactivepixels/eko.git
$ cd eko && npm install

First run

Launch EKO and choose a source from the top bar:

• Local — point EKO at a folder of music; it scans tags and builds a library.
• Server — connect to your Navidrome / Subsonic server with its URL and your credentials.

Pick an album, hit play, and open the deck to see the signal path and EQ.

Architecture

EKO is a Tauri 2 app: a Rust core for all audio, and a React + TypeScript frontend for the UI. Everything plays through one native engine — there is no Web Audio path.

// the audio pipeline
file / Navidrome stream
   → symphonia decode
   → resample only if needed · EQ (biquad) · volume
   → cpal output @ the file's sample rate
   → CoreAudio: device set to match → your DAC

• Engine (src-tauri/src/engine.rs) — streaming decode into a growing buffer, a real-time cpal callback, and a Rust FFT spectrum.
• CoreAudio (src-tauri/src/coreaudio.rs) — sets the output device's hardware sample rate to the file's, and reads it back so the seal is honest.
• Frontend — Zustand store mirrors engine state; the UI is all in src/player/.

Bit-perfect

"Bit-perfect" means the samples in the file reach your DAC unchanged. Most players resample everything to one system rate first; EKO doesn't. It outputs the file's exact rate and switches the device to match — so nothing in macOS resamples behind your back.

The path stays bit-perfect when volume is at 100%, the EQ is flat or off, and the device supports the file's rate. Touch any of those and EKO tells you — it never claims bit-perfect when it isn't.

Verify it yourself

Open Audio MIDI Setup while playing different-rate tracks — you'll see the device's Format follow the music (44.1 → 48 → 96 kHz). That's EKO matching the rate.

Signal path

The deck shows a live chain from source to output, with a seal that lights only when the path is pristine:

When EQ or volume is engaged, the seal switches to a warning glyph and spells out what's altering the signal (EQ, VOLUME, RESAMPLED).

Output & DAC

Click the OUTPUT node in the signal path to choose a device. EKO sets that device's hardware sample rate to match each track and remembers your choice. While playing, EKO owns the device rate (like Roon / Audirvana).

Equalizer

A true 10-band biquad EQ (60 Hz – 16 kHz) with a preamp and presets. Drag a band or pick a preset. Flat = bypassed, so EQ never costs you bit-perfect when you're not using it.

Keyboard

Building

# run in development (hot reload)
$ npm run tauri dev

# produce a distributable .app
$ npm run tauri build

Project layout

src-tauri/src/
  engine.rs      # native audio engine
  coreaudio.rs   # macOS device rate-matching
  metadata.rs    # tags + cover art
src/
  audio/         # engine bridge
  store/         # Zustand state
  player/        # UI + neu.css

Contributing

PRs welcome. The moat is fidelity and design — keep changes faithful to the neumorphic language, and never break the bit-perfect bypass. See CONTRIBUTING.md and docs/ in the repo for the full picture and what's next.

EKO · MIT licensed · The native Mac player for your self-hosted music.