A horn of improved, compact and efficient construction, formed of minimum numbers of components, is characterized by integrally formed parts which facilitate assembly of the horn and which increase the magnetic flux generated by the horn and the efficiency thereof, establish circuit paths within the horn without the need for separate conductors, and present terminals exteriorly of the horn for being connected with circuitry for operating the horn. The horn includes a housing having an open end and relatively imperforate wall areas, a bracket of magnetically permeable material supporting an electromagnetic coil within the housing, a diaphragm positioned over and closing the open end, a striker of magnetically permeable material connected with the bracket and operatively associated with the coil for repetitively striking the diaphragm to generate noise, and a cover having a sound directing port positioned over the diaphragm. The striker is normally urged against the diaphragm, and the bracket has portions which extend from one pole of the coil to a position adjacent the other pole for generating thereat a strong field of magnetic flux for attracting the striker away from the diaphragm. A pair of coil terminals and a terminal connected with the striker extend exteriorly of the housing, and the horn is mountable on a substrate having circuitry for connecting with the terminals and housing and for selectively applying a d.c. voltage thereto to operate the horn.