SPECTRA listens to whatever your computer hears and redraws it, every frame, as glyphs. It runs in the browser with nothing to install.
Open the visualizerTwo passes. Underneath, a Milkdrop/Butterchurn WebGL pass builds the moving image from the audio's frequencies. On top, a GLSL shader rasterises that image into characters: every cell measures the brightness beneath it and picks a glyph from a real monospace font atlas, ordered from least to most ink, then tints it through the scene's shadow-to-highlight colour ramp.
Press D to change the cell size, from fine 9px type to chunky 28px blocks.
A scene is not a palette swap. It sets the glyph set, the colours, the grain and the image treatment. THE MATRIX draws in Katakana and phosphor green; GAME BOY posterises to four shades of LCD green with block characters; NOIR is pure black and white with the occasional crimson spark; TRON uses 01|/[] against hard scanlines.
Each scene multiplies by hundreds of Milkdrop presets (← →) and four densities, so the same track rarely looks the same twice.
Free: every scene, every preset, unlimited use, no account. Recordings and the OBS output carry a small corner mark; SPECTRA Pro, a one-time MX$279 (about US$15), removes it and covers commercial use.
Open SPECTRA