English: A large horn loudspeaker made by Racon Electric Co., New York in the 1920s for use in movie theaters and auditorium sound systems, from a 1928 magazine advertisement. Horn loudspeakers were used almost exclusively for large area sound systems into the 1930s since high power cone loudspeakers were not developed and horns could produce 10 times the sound power of a cone for a given amplifier output. Racon specialized in these large theater horns. The speaker consists of a coiled exponentially widening sound tube driven at its narrow end by a compression driver consisting of a small metal diaphragm vibrated by a powerful electromagnet. Since horn loudspeakers had a lower cutoff frequency, large horns with long air columns and wide mouths like this were required to reproduce bass frequencies accurately. It was made of fabric impregnated with a cement hardener, which did not resonate with sound waves as a metal horn would.

Alterations to image: cropped out surrounding advertising copy, which said in part: Racon Exponential Air-Column Horns are made in all shapes and sizes up to 6 feet square for Theatres and Auditoriums. Maximum Air Column in minimum space.