Abstract: A loudspeaker protective unit for protecting a loudspeaker device against an excessive input current includes a lamp connected in series with the loudspeaker unit. The lamp is housed in a casing exhibiting light-sealing properties formed of an electrically conductive material, and is sealed with a sealant exhibiting a predetermined electrical conductivity. The spacing between lead lines of the lamp housed in the casing is of a preset value. An inert gas is sealed within a main lamp body unit and a preset voltage is applied to the main lamp body unit. When the voltage is applied across the lead lines, an electrical discharge is produced to interrupt the current flowing through the filament so as to prohibit a temperature rise in the lamp.

Abstract: The present invention is relative to a loudspeaker protective unit for protecting a loudspeaker device against an excessive input. The loudspeaker protective unit includes a lamp (15) connected in series with the loudspeaker unit for protecting the loudspeaker unit against an excessive input. The lamp (15) is housed in a casing (16) exhibiting light-sealing properties. The casing (16), housing the lamp (15), is formed of an electrically conductive material, and is sealed with a sealant exhibiting preset electrical conductivity. The spacing between lead lines (153A), (153B) of the lamp (55) housed in the casing (56) is of a preset value. A preset inert gas is sealed within a main lamp body unit (151) and a preset voltage is applied to the main lamp body unit (151). When a preset voltage is applied across the between lead lines (153A), (153B), an electrical discharge is produced to interrupt the current flowing through the filament (154) to prohibit temperature rise in the lamp (55).

Abstract: A diaphragm for capacitance type loudspeaker is disclosed. The diaphragm uses a conductive high polymer layer as a conductor formed on a high molecular film of PET or the like by treating the high molecular film in a water solvent solution containing a conductive high molecular monomer, a chemical oxidizer and a dopant. The conductive high molecular monomer is selected from the group consisting of pyrrole, aniline, thiophene and derivatives thereof.

Abstract: A speaker cabinet includes a baffle plate having at least one aperture for mounting a speaker unit, the baffle plate having a plurality of small areas over its entire surface and so constructed and arranged that the sound waves propagated along the surface of the baffle plate are scattered.