The instrument is typically made of metal and is cylindrical. Inside the cylinder is a type of fan-blade which, when the performer blows through one end, spins and creates the sound. The faster the performer blows, the faster the fan-blade moves and the higher the pitch the instrument creates. Conversely, the slower the performer blows, the lower the pitch.
Acme is the trade name of J Hudson & Co of Birmingham, England, who developed and patented the Acme Siren in 1895. It was sometimes known as "the cyclist's road clearer".
^"Acme Siren". Virginia Tech Multimedia Music Dictionary. Virginia Polytechnic Institute and State University. Archived from the original on 28 August 2006. Retrieved .
^Xenakis, Iannis; Olivier Messiaen (1985). Arts-sciences, Alloys: The Thesis Defense of Iannis Xenakis, Oliver Messiaen, Michel Ragon, Olivier Revault D'Allonnes, Michel Serres, and Bernard Teyssèdre. Pendragon Press. p. 118.