The Musical Siren

The adventure started over thirty years ago when an air raid siren fell into the hands of Franz Clochard. Realising the potential for the air raid siren to interpret the complete musical scale, Franz was hooked. This was the start of a long, rich, artistic journey: an amazing experience filled with surprising encounters.

It has culminated in the creation of the world’s only Siren Orchestra, made up of seven musical Sirens: a piccolo, two sopranos, two altos, a tenor and a bass. The orchestra is conducted by robotics: 71 control systems piloted by 105 control loops, to allow the sirens to interpret the musical score.

HOW A STANDARD AIR RAID SIREN WORKS
The siren produces sound by sucking in air (solid arrows) as it rotates which is then fragmented to create a sound wave. The air is then forced through the horns (dotted arrows).
The faster the rotation, the higher and louder the sound.

HOW THE MUSICAL SIREN WORKS
In order to make the siren sing, there are three principles involved:

• precise control of the turbine rotation speed allows the Siren to produce every note in the musical scale.
• depriving the Siren of the air it needs to produce sound gives attack, expression and subtlety
• muting the horns modifies the volume of the sound produced, allowing closer proximity to the public.

Precise and highly responsive technology regulates turbine speed and controls airflow, keeping the Siren in tune and giving the sound tone and colour