Abstract: An acoustical transformer or "phasing plug" for coupling the sound from an annular diaphragm to the throat of a compression-type loudspeaker. The phasing plug in the invention has the general shape of a doubly-truncated cone with an annular surface located on the larger end of the truncated cone and positioned adjacent to the diaphragm. The conical surface of the cone has spaced radial slots or channels formed therein connecting the truncated surfaces of the cone. These channels form air passageways for propagation of sound waves. The walls of the slots or channels are tapered such that the cross-sectional areas of the channels increase from their inlet ends near the speaker diaphragm, towards the outlet ends, positioned at the throat of the horn. The phasing plug provides an improved impedance match between the output of the annular diaphragm and the input of the horn.

Abstract: A speaker horn is adapted for coupling to a speaker drive assembly and for dispersing incident sound energy in a 360.degree. radial pattern. The horn includes two sound-dispersing structures for making a passageway generally symmetrical about a longitudinal axis. An inserted structure restricts the movement of the incident energy in one axial direction and includes a plug which is nested in close proximity to a wall of a receiving structure at the input end of the receiving structure. The receiving structure restricts the propagation of the sound energy in the other axial direction to cooperate with the inserted structure in defining the passageway in a radial pattern between the two structures. The plug includes a concave face perpendicular to the longitudinal axis for receiving incident energy. The plug, in cooperation with the inner walls of the receiving structure, effects a change in phase of sound energy encountering the plug, and acts as an intensity amplifier for incident sound energy.

Abstract: A sound projection system comprising means defining a longitudinally extending acoustic channel which is acoustically open at a front end of the channel and acoustically closed at a rear end and at sides of the channel, a loudspeaker having a cone diaphragm operating into the channel at the rear end of the channel, and a longitudinally extending member mounted within the channel directly in front of, and in alignment with, the loudspeaker so as to restrict the free space within the channel, the cross-sectional area of said member varying along its length.

Abstract: A horn speaker comprising a diaphragm positioned close to a throat and side walls forming sound passages for radiating the vibrations of the diaphragm effectively as sound waves from the mouth of the speaker.

Abstract: An acoustical transformer or "phasing plug" for coupling sound from a speaker diaphragm to the throat of a horn. The phasing plug of the invention is in the general shape of a dome on one side and a truncated cone on the other, and has evenly spaced radial slots or channels formed therein, these slots forming air passageways for propagation of the soundwaves. The walls of the slots are tapered exponentially from their inlet ends at the speaker diaphragm towards a flat plane outlet at the throat of the horn, to provide an optimum impedance match between the output of the diaphragm and the input of the horn; the sound channels formed by the slots exponentially increasing in area between their inlets and outlets. Transformation from a spherical wave front at the input to a plane wave front at the outlet is assured by the shaping of the channels to make the distances between corresponding points at the channel inlets and outlets equal to each other.