Abstract: Highly directional response patterns can be obtained by connecting microphones or loudspeakers with tubular coupling path structures. The coupling paths comprise a plurality of elements (110,111 . . . 157) arranged in pairs (110,111; 112,113; . . . 156,157) so that for every element (110) below a center line (102) there is an element (111) above the line. Furthermore, the relationship between the element pairs is nonlinear. The desired directional response comprises one main lobe and a plurality of substantially smaller lobes below a determinable threshold value. The elements may be a bundle of tubes (90) or a plurality of apertures (110,111, . . . 157) in a single tube (100).

Abstract: A miniature sounder having a diaphragm closing one end of a tuned chamber. The other end of the chamber communicates with the interior of a tuned housing. The chamber and housing are both tuned to the desired oscillating frequency of the diaphragm with the chamber resonant frequency comprising substantially three times the desired frequency and twice the housing resonant frequency.

Abstract: An exponential folded horn loudspeaker enclosure is built so that all of its components are coaxial with respect to a line that is equidistant from three cooperating surfaces, including floor or ceiling, as well as the customary two walls of a corner. Perfect symmetry with all three cooperating surfaces permits a smooth transition to these surfaces, so that they become a balanced extension of the exponential horn, more than doubling its effective length. Approaching the configuration of a large ideal horn, this geometry is uniquely free of discontinuities and artificial resonances that are needed in other enclosures for boosting low frequency response; therefore, efficiency and fidelity of low frequency response are greatly increased over other enclosures of comparable size.

Abstract: A portable receiver includes a housing which operates as an acoustical amplifier to increase the output level of the audio signals produced by a sound transducer. The sound transducer is located within a cavity in the housing and emits audio signals into the interior of the housing. The housing has vents located in its walls to permit the audio signals produced by the sound transducer to pass freely to the exterior of the housing. The vents are dimensioned such that the resonant frequency of the housing lies approximately at the center of the frequency range of the signals produced by the sound transducer. Matching the resonant frequency of the housing to the output signals of the transducer causes the housing to operate as a tuned resonator which amplifies the output signals of the transducer.

Abstract: An acoustic crossover speaker enclosure comprising a multi-sided box having an apertured baffle supporting a horn which in conjunction with the interior of the box defines an air chamber. The horn is supported in an upright position such that the throat of the horn opens at the baffle end of the box where the front end of a driver projects into the horn throat, while the back side of the driver projects into the air chamber of the box. The horn opens at the top end of the box wherein sound waves emitted from the mouth of the horn are laterally reflected by means of a sound deflector panel. The air chamber transmits sound from the rearward side of the driver to a bass reflex port in one wall of the box such that a sound radiated from the rear of the driver may be added to the sound emitted from the front of the driver.