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Case study: Synchronized audio application – July 14, 2021 fireworks display – Orléans

Electroson Studio proposed a fully dematerialized solution guaranteeing optimal audio transmission quality and minimum latency in communication and synchronization with the pyrotechnic system for this 20-minute show which usually brings together 20,000 spectators.

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On the occasion of the celebration of the French National Day 2021 in Orléans , the traditional pyromusical fire had to be adapted to the health constraints in force.

The cancellation of this event was not an option, both for the municipality of Orléans and for its spectators, but there was however no question this year for the municipality to propose a gathering of spectators at the ends of europe bridge, from which fire would be drawn.

The sound diffusion could not be done with a traditional sound system, but thanks to a device which would allow spectators to be autonomous in L'listening to the soundtrack a spectacle.

It is in this perspective thatElectroson Studio took up the challenge, proposing a completely dematerialized solution guaranteeing a optimal quality of audio transmission and the minimal latency in the communication and the synchronization with the pyrotechnic system for this 20-minute show which usually brings together 20,000 spectators.


The soundtrack pyromusical fire was listenable during the event on the website, reachable without the need to install an application, on connected devices, such as smartphones Where tablets. This web interface is compatible with the main operating systems (android and iOS). Its use is free for the viewer, and free of rights and access.

A few days before the event, spectators are invited to visit the website so that the soundtrack of the fire is automatically preloaded in the background (no user action required).

A simple connection to the website a few minutes before the start of the pyromusical fire allows the automatic trigger soundtrack from the start of the show.


HAS the precise moment where the show is started by the fireworker, the fire firing system sends out a pulse (called a time code) to our device which automatically synchronizes and inform via 4G network all viewer connected devices. The soundtrack then begins to play on the viewers' devices..

The key elements:

  • the shooting table from the artificer sends us a time code SMPTE, via a timecode player connected to a server Modulo Pi
  • upon receipt of the show start timecode on the Modulo Pi, this informs instantly our Web server thanks to a query who provides theprecise timestamp of the start of the fire
  • a server hosted at OVH is the center of the installation. It allows users to connect to listen to the soundtrack. It is to him that the time code departure of the show which is then retransmitted to all persons connected to the website
  • the data storage is replicated on the content distribution network (CDN) CloudFlare in order to distribute the load bandwidth and limit slowdowns caused by the server infrastructure

The audio media is directly read by connected devices spectators, rather than using a system of audio streaming. This method allows to limit latency as much as possible not relying on a streaming system (whose latency can reach one minute): after downloading, the audio plays in its entirety on the web browser of the viewer's smartphone thanks to HTMLAudioElement web components. The developed tool is thus suitable for modern devices allowing audio playback in their web browsers (see compatibility list).


4,390 connected devices downloaded the soundtrack on July 13 by logging into the site for the first time that day.

Despite the inclement weather, the website recorded between 2,700 and 3,500 devices connected during the fire.

A device making it possible to broadcast sound for a group of 4 to 5 people on average thanks to its loudspeaker, it is therefore between 10,800 and 17,500 people who were able to take advantage of this innovation to enjoy this moment while respecting barrier gestures, outside, on the banks of the Loire, or warm at home watching the show through the window!

Do you also want a dematerialized system which would allow spectators to have access to a transmission of the soundtrack without grouping people and in compliance with health constraints?

Your event is huge proportion (fireworks visible from several places), visible from afar (sound and light at the foot of which the spectators cannot go), or would require a excessive sound system to capture the expected number of spectators?

contact us so we can discuss it!