Abstract: A horn speaker in which a cooling device is attached near a moving coil which vibrates a diaphragm. The cooling device may be attached to the inner periphery of a bobbin which is connected to the diaphragm and around the outer periphery of which the moving coil is wound.

Abstract: By adding a secondary magnetic piece with a partially open magnetic circuit to the front surface of a yoke connected to a primary magnetic piece, the magnetic flux leakage from the main magnetic piece is reduced on one hand and the magnetic flux extending across a magnetic gap is intensified through formation of a favorable magnetic field. This horn speaker is particularly useful in a ship where a horn speaker as an alarm is often required to be placed near magnetically sensitive equipment such as a compass.

Abstract: A reflex horn speaker with a waterproofing device for use on a ship or the like is disclosed. The reflex horn speaker comprising a sound generator, an inner cylindrical horn, a conical reflector concentrically arranged around the inner horn, and an outer cylindrical horn concentrically arranged around the reflector, is provided with a waterproofing device such as a valve, mounted to the closed front end of the reflector, which can open or close the front opening of the inner horn in order to prevent water and/or moisture from coming in the inner horn when it is not used.

Abstract: A horn speaker wherein a pole piece of a yoke is arranged inside an annular permanent magnet and a moving coil which vibrates a diaphragm, is arranged in an air gap between the pole piece and the annular permanent magnet. A plurality of linear grooves are formed in the front surface of the pole piece in order to suppress the generation of the heat of the pole piece and the moving coil.

Abstract: A coldproof reflex horn speaker comprising a frame, a magnet mounted thereto, a diaphragm having a voice coil in its periphery, and inner and outer horns, which is provided with an electric heater device disposed to the outer horn in order to prevent ice and snow from being frozen thereon in cold circumstances.

Abstract: An electric horn is disclosed which has two electromagnets which are alternately and repeatedly energized so as to move a diaphragm to and fro in opposite directions. As a particular feature, a controller is disclosed which energizes these electromagnets at a frequency which is dependent upon ambient air temperature, so as to keep the wavelength of the emitted sound constant to provide a better match for the horn trumpet of the electric horn and cause better resonance therewith.