Audiences at large concerts and stadiums have long become part of the light show. But how exactly do you sync thousands of devices? Here is a breakdown of three real approaches.
PixMob: infrared wristbands
PixMob is a Canadian company with over 20 years of experience. At Taylor Swift, Coldplay and other tours, special IR wristbands are handed out to the audience. The bracelets receive commands via infrared transmitters placed around the venue.
Pros: extremely precise sync, bright colours, works reliably even in bright lighting. Cons: you have to buy, distribute and collect tens of thousands of devices. Wristbands are expensive (Coldplay spent around €400,000 on wristbands for a single concert). Logistics, charging, disposal.
CUE Audio: sound instead of network
CUE uses data over sound. Data is transmitted via ultrasonic or audible frequencies from the speakers. Viewers scan a QR code, open a page in the browser, and sound from the stage controls the phone lights.
Used at the 2026 World Cup. Works without an app, through the browser. Pros: no equipment to distribute. Cons: depends on sound quality and venue acoustics, can suffer from background noise or jamming.
GROMKA: ultrasound without app or internet
Our technology also uses sound, but in the ultrasonic range. Viewers scan a QR, the browser opens the page, and ultrasound from the stage syncs the flashlights. No internet required, works even when mobile networks are jammed (as in planetariums or large stadiums).
Pros: no wristband logistics, works in any indoor space, right after the show you can launch promos and prize draws in the same browser. We can do not only flickering but drawings, waves, complex patterns. Technology is patented (patents in process). Cons: best effect in relatively dark venues.
Technology comparison
- Sync accuracy: PixMob excellent, CUE good, GROMKA high (ultrasound)
- Cost: PixMob very high (purchase + logistics), CUE and GROMKA much lower
- Logistics: PixMob distribute and collect wristbands, CUE and GROMKA only QR on screen
- Works without internet: PixMob yes, CUE partially, GROMKA yes (ultrasound)
- Post-event contact: PixMob almost none, CUE possible, GROMKA promo and draws immediately in every viewer’s browser
- Complexity of effects: PixMob coloured wristbands, GROMKA drawings and waves from the entire hall’s flashlights
More about how our ultrasound actually works in the article How the light show works. The CUE case at the 2026 World Cup is in a separate post.
The format works at concerts, festivals and stadiums. More details in the Concerts and festivals and Sport sections. Drone show alternative is covered in a separate article.
