How do you run a live music visualizer on a projector or second screen?

Set-up in four steps

1. Connect the display. Plug the laptop into the projector or second screen and set it as an extended display (or mirror it if you want to watch the same thing).
2. Open Live mode and allow the microphone. Go to groovalizer.space/live in the browser. When it asks for microphone access, allow it: that permission is how the visuals hear the room. If your sound system feeds a USB interface or line input, select that device in your system sound settings first.
3. Go fullscreen on the show display. Drag the browser window onto the projector and click to enter fullscreen. The visuals fill the screen with no browser chrome.
4. Choose how presets cycle. Cycle at random through the whole library or through one of your playlists, every 15, 30, or 60 seconds, or set it to manual and change presets yourself during the set.

What it is good for

• Parties and house shows. A projector on a wall, the room’s sound through the laptop mic, presets rotating on their own all night.
• DJ sets. Feed the mixer’s booth output into a USB interface so the visuals follow the actual mix, and switch presets manually on the transitions.
• Bands and small venues. Beat-reactive backdrops without a lighting rig or a VJ laptop full of software.
• Ambient installs and listening rooms. Build a playlist of slow, luminous presets and set the cycle to 60 seconds.

The MilkDrop tradition, without Winamp

Live visuals on a wall while music plays is what MilkDrop was for. Groovalizer runs its open-source successor, projectM, compiled to WebAssembly, so the same preset format (thousands of community .milk presets plus Groovalizer’s own) renders at 60 fps in a browser tab on your GPU. Butterchurn does the playback half of this too; Groovalizer adds playlists, timed cycling, and the studio for making a file of it afterwards.

Rendering is entirely local (the GPU in the laptop does the work), but preset files load from the site as they cycle, so keep the tab online and load the page before you start.

Practical tips

• Use Chrome or Edge on a laptop with a discrete GPU for the smoothest frame rate; close other tabs.
• Set the display to the projector’s native resolution rather than scaling a 4K desktop down.
• If the visuals barely move, the input is too quiet: raise the input gain in your system settings, or move the mic nearer the speakers.
• Build the playlist in the studio beforehand, with a couple of calm presets for the quiet parts of the night.