Abstract: A loudspeaker for projecting sound over a listening area having a driver and a horn in which the horn has a coupling portion communicating at an interface with an outwardly flaring portion, the horn forming an elongated slot at the interface and being provided with means for controlling the sound energy along the axis of elongation of the slot, namely a slot which is narrower at one end and flares outwardly to the other end, or a plurality of transverse veins dividing the slot and sound channel.

Abstract: An adjustable mount for a loudspeaker having a plate adapted for mounting on a surface or the open side of a junction box. The plate has an indented part-spherical surface which accommodates a ring with an outer part-spherical surface. The ring has an aperture extending therethrough and an elongated slot, and a first hollow tube is rotatably disposed in the aperture and a second hollow tube is translatably disposed in the slot. One of the tubes extends through an opening in the recess of the plate and the other tube is mounted on the loudspeaker with the conductor for energizing the loudspeaker extending through the first and second tubes. A web extends radially inward of the ring and has bifurcations at the end thereof disposed on opposite sides of the portion of the conductor between the first and second tubes. The first and second tubes have external threads which are engaged by locknuts for securing the ring on the plate and on the loudspeaker.

Abstract: A loudspeaker with a voice coil reciprocally disposed in a magnetic gap provided with means for conducting heat outwardly from the gap comprising a flat circular web disposal in abuttment with the magnetic structure and extending between a cylindrical collar which confronts the voice coil former to a circular ring integral with the frame of the loudspeaker and including vanes extending from the web between the collar and ring. The voice coil former is limited to axial motion by a pair of spaced flat disks mounted at their centers on the central pole piece normal to the axis of motion and on the coil former at their perimeters.

Abstract: A loudspeaker system for low frequencies has a manifold chamber into which oppositely mounted and aligned woofer units radiate sound. The chamber radiates the sound perpendicularly to the woofer axes, either directly into space or into a horn. An additional back woofer may radiate directly in the perpendicular direction.

Abstract: A speaker system including a frusto-conical diaphragm, and a phase plug mounted within the volume formed by the diaphragm, the phase plug including a pair of substantially diametric open slots extending across the diaphragm and through the phase plug, with each of the slots having substantially rectangular cross sections transverse to the axis of the diaphragm.

Abstract: A battery charging system including a plurality of transformers each having a primary winding, a secondary winding, and a tertiary windings, the primary windings being connected in series forming a "shared primary", a first switching network for connecting a DC voltage across the shared primary winding, in alternating polarity over successive half-cycles of a clock signal, for causing voltage pulses to be induced into the secondary and tertiary windings of the transformers, a second switching network responsive to the magnitude of primary current for shorting the same or different combinations of the tertiary windings, thereby shorting the associated transformers, over each half-cycle of a clock signal, for controlling the magnitude of charging current to the batteries, and a plurality of rectifiers for rectifying the AC voltages developed in each secondary winding, respectively, for providing charging current to the battery.

Abstract: A high-frequency constant-directivity horn including a relatively large throat driver and a relatively large throat for receiving sound from the driver, further includes a pair of vanes mounted wholly within the throat, respectively above and below the longitudinal axis in a vertical plane, for effectively dividing the throat into three smaller "pseudo horns" for directing and shaping sound waves from the transducer up to the point of termination of the vanes, beyond which the individual wavefronts mix within and fill a slot in a middle section of the horn, forming a coherent wavefront for passage into a front section of the horn and transmission therefrom, substantially free from wave interference and beaming effects.

Abstract: A power supply for providing an output voltage amplitude modulated by a command signal, includes a rectifier for rectifying the command signal, a comparator network for comparing the instantaneous rectified level of the command signal with a plurality of predetermined reference voltages, for producing a plurality of phasing signals, respectively, for operating a switching network to (1) alternately and successively connect positive and negative polarity DC voltages to the one ends of a primary windings of a plurality of transformers, and to (2) connect either the positive or the negative DC voltage to the other ends of the primary windings in different combinations, over each half-cycle of a clock signal, for producing in a common secondary winding for the transformers the amplitude modulated output voltage. Another rectifier may be provided for rectifying the AC output voltage, for producing a DC output voltage amplitude modulated by the command signal.

Abstract: An acoustic equalizer adapted for use with a microphone includes a resonator plate having front and back faces, a lip surrounding the plate and defining a first air cavity in the back face of the plate, and a plurality of apertures formed through the thickness of the plate, which apertures communicate with the first cavity. A boss is formed centrally on the front face of the plate. The boss is closed ended on one side and hollow interiorly to define a second air cavity. The first and second cavities communicate with each other through a central opening formed in the plate.

Abstract: A multiple driver manifold for coupling four high frequency drivers to a single horn. Two drivers are mounted in a "Y" or "skewed" configuration, and two additional drivers are mounted so as to be directly opposed to one another along a line perpendicular to both the horn throat on-axis direction and the general plane of the "Y" configuration. Sound radiated transverse to the horn on-axis direction by the opposed drivers is "ray-reflected" by a unique ray-reflection summation plug located at the internal hub of the four acoustic paths.