Tag Archives: Diaphone

The diaphone was a noisemaking device best-known for its use as a foghorn: it could produce deep, powerful tones able to carry a long distance. Diaphones were also used at some fire stations and in other situations where a loud audible signal was required.
The diaphone horn was based directly on the organ stop of the same name invented by Robert Hope-Jones, creator of the Wurlitzer organ. Hope-Jones‘ design, based on the vibrations in air created by a slotted piston moving within a correspondingly slotted cylinder, was adapted and patented by Professor John Pell Northey of the University of Toronto, who added a secondary compressed air supply to the piston to power it on both forward and reverse strokes and create an even more powerful sound. The entire horn apparatus was driven by a compressor.
To manufacture the new equipment, Northey set up the Diaphone Signal Co. at Toronto in 1903. It manufactured a range of diaphone models: the large „Type F“, which created a tone of about 250…