Horn speaker

Claim 1

A horn speaker comprising a diaphragm, a side wall, and at least one interior sound partition, forming at least two passages for radiating sound waves emitted from the diaphragm, the horn speaker having a substantially straight principal horn axis and a generally planar mouth surface positioned substantially in parallel to the inlet face of the horn, the area of each sound passage in section taken along a plane perpendicular to the principal horn axis increasing continuously at a substantially constant rate of area expansion from a throat to the plane of the mouth in the direction of the principal horn axis, the horn speaker being characterized in that said at least one interior sound partion has inner and outer surfaces, at least said outer surface being curved along the principal horn axis to give substantially the relationship for each sound passage represented by the equation: l = - f + √(lo + f).sup.2 + y.sup.2 wherein l is the effective length of the sound passage for propagating sound waves from the diaphragm to a point at a distance of y from the intersection of the principal horn axis with the mouth plane, the point being positioned on at least one first straight directional line contained in the mouth plane and passing through the intersection, lo is the length of the principal horn axis and f is a virtual focal distance; and wherein: the mouth surface is generally circular, and every diametrical direction of the plane of the mouth substantially coincides with the directional line; said at least one interior sound partition, as seen in cross section parallel to the mouth plane, is annular in shape and coaxial with the principal horn axis, whereby said at least two sound passages defined by said at least one interior sound partition and the side wall, as seen in cross section parallel to the mouth plane, include a circular sound passage coaxial with the principal horn axis and at least one annular sound passage concentric with the circular sound passage; and at least one of said at least one interior sound partition defines a plurality of circumferentially spaced bores, or passageways, through the sound partition.