Review 07 · Diversions
VIZZI.
A browser visualiser that treats sound as something to measure: one analysis per frame shared by every tile, a raw microphone, a VU meter solved to the standard. It is also over a megabyte of script.
- Tested 27 September 2026, 20:10–20:16 UTC
- Where the work happens your own sound, on your own machine
- Against Butterchurn, Webamp, Specterr
1What it is, and who it is for
VIZZI draws what it hears. Point it at the microphone or drop a track on it, and its modes (oscilloscope, vectorscope, spectrum automata, a VU meter and many more) fill a stage of 1, 4, 9 or 12 tiles, each with its own effects from a set of sixteen. A deck adds tempo, pitch, EQ, filter and echo; a seven-character code saves the desk; and it records video or audio in the browser.
It is for musicians, DJs, VJs and anyone who wants to see sound without installing software.
2How it works
The audio work is the Web Audio API in your browser. One AnalyserNode (fftSize 2048, smoothing 0.72) measures the signal once per frame, and the same reading goes to every visible tile, so twelve tiles cost one analysis (engine.js 621–627; app.js 4–8). The microphone opens with echo cancellation, noise suppression and automatic gain all off, so the modes see the room as it is, and none of it reaches your speakers (engine.js 666–687). A dropped file is decoded locally; the engine's header states nothing is uploaded (26–29).
The VU meter is solved to the ANSI C16.5 ballistics, 99 per cent of a step in 300 ms with 1.5 per cent overshoot, sub-stepped at 1/240 s so it reads the same at 60, 30 or 20 frames a second; the code records that the naive version took 0.333, 0.400 and 0.450 s at those rates (readouts.js 33–34, 90–100). The beat detector even says what it is: energy over about 1.5 s with a floor and a refractory period, not a musical downbeat.
Two small server pieces exist: code.php stores a shared desk under its code, forty saves per address per hour, and music.php keeps the site's track list behind a password. Recording runs MediaRecorder on the page's canvas, as WebM or MP4 (share.js 225–297).
3The test
We loaded the page from the local 537 copy, counted registrations in its source, and called its two server endpoints.
Loaded the page.
HTTP 200, 147,358 bytes of HTML. Scripts in vizzi/assets/js: about 1.1 MB across 22 files and 20,225 lines; the largest, app.js, is 337,512 bytes.
Counted mode and effect registrations.
46 mode register() call sites in nine files, library.js the largest with 16; 16 effects in fx.js, matching the page's 'sixteen keys'; stage layouts 1, 4, 9 and 12.
Called music.php and an unknown desk code.
music.php: HTTP 404, {"ok":false}; the list needs the password. code.php: 404 for an unknown code.
4Against the field
Each rival was read on its own pages on the test day. Pencil marks what it does better; red, where VIZZI goes further.
Butterchurn
github.com/jberg/butterchurn · checked 27 September 2026, 20:17 UTC, from the project page (its demo site answered 503)
An open-source, MIT-licensed WebGL implementation of the MilkDrop visualiser, which loads MilkDrop presets and blends between them.
In pencil
- It plays MilkDrop presets and blends smoothly between them, as an MIT library anyone can embed.
In red
- Measurement-grade readouts as well as pictures: an ANSI-ballistic VU meter, an oscilloscope, a vectorscope.readouts.js 90–100; scopes.js 202–210
- Up to twelve different modes on one stage from one shared analysis, each tile with its own effects.index.html 779–782; app.js 4–8
Webamp
webamp.org · checked 27 September 2026, 20:18 UTC
Winamp 2 reimplemented in HTML5 and JavaScript, MIT-licensed, with full skin support and Butterchurn's MilkDrop visuals built in.
In pencil
- A familiar player with classic Winamp skins and MilkDrop visuals built in.
In red
- It listens to the microphone as well as files, with the browser's voice processing switched off for an honest picture.engine.js 666–687
- A seven-character code recreates the entire desk; the same desk always makes the same code, rechecked on the server.share.js 13–17; code.php 5–11
Specterr
specterr.com · checked 27 September 2026, 20:19 UTC, from its own blog (its home and pricing pages rendered empty to our fetch)
An online maker of music-visualiser videos. Its blog says the free tier makes 720p, 30 fps videos up to five minutes long, two a day, watermarked.
In pencil
- Built to produce a finished, shareable music video from a track.
- A lyric-video maker as well, linked from its own site menu (seen on its blog page, 27 September 2026, 21:06 UTC).
In red
- It is live, reacting to the room through the microphone in real time instead of rendering a file afterwards.engine.js 666–687
- It records on your machine: MediaRecorder on the page's own canvas, saved straight to a file.share.js 225–297
5Where it falls short
- Weight. About 147 KB of HTML and some 1.1 MB of script before anything draws is a lot to ask of a phone.
- Real-time capture only. It records the canvas as it plays; it cannot render a polished video with titles or lyrics.
- No presets from elsewhere. The modes are the site's own; community MilkDrop presets cannot be loaded.
- A locked shelf. The site's track list sits behind a four-digit password; without your own track or a link, you get the bench tone or the microphone.
6The verdict
VIZZI is a measuring instrument that also makes pictures, with raw input, one shared analysis and a meter built to the standard, and it asks a great deal of a phone to get there.
- In red ink
- One analysis for twelve tiles, a raw microphone, ANSI VU ballistics, a whole desk in seven characters, and local recording.
- In pencil
- For MilkDrop presets, Butterchurn or Webamp; for a finished release video, Specterr.