Phosphor is now on the Mac App Store. A music visualizer for macOS.

A modern MilkDrop has been hard to find for years — most options are dead, Electron ports, or priced like a DAW. So Phosphor got built from scratch.

Phosphor listens to whatever’s playing on your Mac — Apple Music, Spotify, a browser tab, a DAW — and turns it into beat-synced animations. No audio routing. No virtual devices. No Soundflower.

Three modes

  • Float. Small borderless window. Tuck it in a corner while you work.
  • Fullscreen. ⌘F. Esc to come back.
  • Wallpaper. Animates the desktop itself, behind your windows. Surprisingly good at low-key parties.

A lot of scenes, eight effects, and a director

Nearly 150 scenes ship with the app — hand-built originals plus ported Shadertoy classics. A handful of standouts:

  • VFD Bars — vacuum fluorescent bars, frequency-domain.
  • Phosphor — CRT phosphor decay. The namesake.
  • Ray-Marched Tunnels — Metal shader, beat-driven camera.
  • Orbiting Satellites — particle bodies on dynamic orbits.
  • Oscilloscope — time-domain waveform.
  • Particle Fields — flow fields driven by spectral energy.
  • Starfields — beat-synced acceleration through depth.

Stack any of these on top of any scene: kaleidoscope, glow, film grain, RGB split, beat-shake, camera wobble, scanlines, chromatic aberration.

Hit R for the director if you don’t feel like driving. It reads the same audio features the scenes do — bass, onsets, tempo, spectral flatness — and picks scenes to match. Drops get Tunnels and VFD Bars. Ambient passages get Oscilloscope or Particle Fields. Plain heuristics, no ML.

Swift and Metal, no shortcuts

Each scene is a hand-written Metal shader. Audio capture uses the Core Audio Process Tap, the supported system-audio path on modern macOS, so every source works without virtual devices or kernel extensions. Detection runs on its own audio thread; the GPU draws on its own clock. Wallpaper mode is a real NSWindow behind the desktop, not a screensaver hack.

Things that turned out to matter

  • Media controls. Pause, skip, and scrub Apple Music or Spotify from inside Phosphor.
  • Recording. Straight to MP4 with audio. Good for clips.

Get it

Mac App Store. One-time purchase, macOS 14.4+, Apple Silicon native.

Feedback at getphosphor.com.