Splitwave

Splitwave is a node-based audio router for macOS. Wire microphones, system audio, per-app capture, and WAV files into a visual graph, run them through a chain of effects — EQ, compression, reverb, limiting, and more — then send the result to speakers or record it in WAV, FLAC, AIFF, MP3, Opus, or AAC.

Installation

Download the latest .dmg from Releases, open it, and drag Splitwave to Applications.

macOS will block the app on first launch ("cannot verify developer") because the binary is not notarized. To allow it, run once in Terminal:

xattr -cr /Applications/Splitwave.app

Then open Splitwave normally.

After each update, Screen Recording permission resets (macOS revokes it when the binary changes and the app is unsigned). To re-grant it: open System Settings → Privacy & Security → Screen Recording, click − to remove Splitwave, then click + and add it back.

Features

• Inputs: microphones, system audio, per-application audio (ScreenCaptureKit), WAV files, virtual device loopback
• Outputs: physical speakers/interfaces, file recording in WAV (16/24-bit PCM + 32-float), FLAC, AIFF, Opus, MP3, AAC (M4A), virtual devices
• Effects: Gain, Mute, Channel Balance, Saturator, 10-band Graphic EQ, Brick-wall Limiter with look-ahead, Compressor (with sidechain), Noise Gate (with sidechain), Stereo Delay, Algorithmic Reverb (Freeverb), Level Meter, EBU R128 LUFS Meter
• Virtual devices: create named virtual audio devices that appear system-wide. Use them to capture loopback audio from any app or to feed processed audio into apps that accept a microphone input (DAWs, Discord, etc.)

Stack

• Frontend: Svelte, Tauri, @xyflow/svelte
• Engine: Rust -- cpal (device I/O), rtrb (SPSC ring buffers), rubato (resampling), hound (WAV), flac-codec, opus, mp3lame-encoder, ebur128
• macOS-specific: custom Swift static library for ScreenCaptureKit, compiled by build.rs via swiftc; CoreAudio HAL FFI for device enumeration; libASPL-based AudioServerPlugin for virtual device driver

Development

Prerequisites

• macOS 13+ with Xcode Command Line Tools (xcode-select --install) -- gives you swiftc and the SDKs Tauri needs.
• Rust (stable toolchain)
• Bun (curl -fsSL https://bun.sh/install | bash)

Setup

bun install
bun run tauri dev

Useful commands

bun run check                      # svelte-check + tsc
bun run generate                   # regenerate TypeScript types from Rust (ts-rs)
cargo check --manifest-path src-tauri/Cargo.toml
bun run tauri build --bundles app  # local .app build

Project layout

src/lib/modules/
  audio/        cpal/SCK bridge, device enumeration, meter store
  flow/         xyflow node graph editor, sidebar, context menu
  pipeline/     pipeline state, snapshot history, ts-rs generated types
  form/         shared form primitives (combobox, slider)
  error/        global error modal (Rust panics + JS errors)
  updater/      auto-update modal + skip-version persistence
  app_info/     OS / app version cache
src-tauri/src/
  audio/        DSP engine, effects, encoders, pipeline DAG
  commands.rs   Tauri command surface
  lib.rs        app entry, plugin wiring, panic hook
src-tauri/native/virtual_driver/
  SplitAudioDriver.cpp  AudioServerPlugin implementation (libASPL)
  Info.plist            CFPlugin manifest