LMT · 4th Lielais Koncerts · Mežaparks, 2025
Twenty thousand phones, one web page each, lit to the music. No wristbands, no app.
Yes, Coldplay's wristbands were the reference. But twenty thousand battery-powered devices that have to be shipped, handed out, collected, charged and eventually thrown away is a lot of plastic for one evening.
Everyone in the audience already carries a bright screen. The better solution was not to add another piece of technology, but to connect what was already there: phones, browsers, a mobile network and the show's timeline. Scan a code at the gate, open a page, hold the phone up when told. No app, no permissions.
01
A page that changes colour is trivial. A page that changes colour at the same instant on twenty thousand phones, in time with a live band, is not. Microphone sync and camera sync were both tried. Neither was precise enough to choreograph.
Global time won. Each phone downloads the whole light script in advance and plays it against a shared clock. No camera, no microphone, nothing a browser would ask permission for.
02
Live shows drift, so every phone has to ask the server "is it time yet?" Twenty thousand phones asking in the same second is a denial-of-service attack on your own client's network, in front of thirty thousand people. LMT's engineers had no documented safe number. So the phones check in in batches, each on its own offset, and get the master time cue just before the show.
03
Twenty thousand people on one cell site, loading the same thing at once. The whole app was cut to 180 KB. Across every phone that is about 3.43 GB for the entire show, less than one person streaming it in HD.
04
To write the show, a custom editor. The song's waveform runs along the bottom, effects sit on it as blocks: solid, strobe, gradient, random, each with colours, speed and loops. Near-millisecond control, which is what the microphone idea never gave.
The cue went out and the bandstand answered. Twenty thousand screens came up together, held the beat and changed colour with the song. No wristbands handed out, none collected, nothing installed.