Abstract: An enclosure for a transduction element incorporates a geometrically shaped acoustically reflective shell. This acoustically reflective shell is shaped so that the inner surface thereof is at a least a section of that shape generated when a parabolic structure is rotated around a line which, lies in the plane of the parabolic structure, is perpendicular to the major axis of the parabolic structure. Such geomtrically generated shapes will have one distinct focal curve. A transduction element placed about this focal curve will, in operation, cause acoustic radiation to be produced which will be characterized by a plane wavefront of coherent radiation. Said device may alternately act as a transducer which produces a 360 degree beam width by placement of a plane wavefront producing transduction means at a position above the acoustically reflective shell and parallel to the plane of the distinct focal curve.

Abstract: This invention comprises a device for transducing the speech of a conference group gathered about a table. It is capable of wireless operation for use with hearing impaired amplification systems and remote conference recording. The device combines an acoustically controlled microphone and antenna system in a single unit with no visible wires, antenna, or electronics. Specifically, a single condenser microphone is mounted at the end of the frustoconical member which is suspended above and perpendicular to a horizontal reflector plate. The diaphragm of the microphone is parallel to the table top. The reflector plate also functions as an antenna in radio versions of the device. An opening at a predetermined specific angle between the cone and reflector plate deflects the sound waves eminating from any conversations about the table directly into the microphone causing it to produce a higher electrical output for those frequencies produced by the human voice.

Abstract: A parametric loudspeaker utilizes nonlinearity of air relative to ultrasonic waves for producing an audio frequency having super directivity, and to thus provide a limited listening area public address system subject to a large listening area by safeguarding listeners by the provision of a framework for intercepting powerful ultrasonic waves and an acoustic filter. The depth and energy consumption of the parametric loudspeaker are reduced by the use of a reflective plate. Arbitrary directivity is obtained by the provision of a mechanism to move an ultrasonic wave radiator or the reflective plate. The parametric loudspeaker and any other loudspeaker may be combined.

Abstract: An acoustical reflector is positioned in such manner relative to a loudspeaker as to reflect all of the indirect sound waves generated as a necessary concomitant to the generation of direct sound waves by the loudspeaker substantially only to the audience area receiving said direct sound waves from the loudspeaker. In an array of a plurality of loudspeaker, each serving one of a plurality of audience areas, acoustical reflectors are positioned relative to said plurality of loudspeakers so that indirect sound waves, generated as a result of the generation of direct sound waves by each of said loudspeakers, are reflected substantially only to the audience area served by said loudspeaker and not to audience areas served by other loudspeakers.

Abstract: Acoustic wave "diffractor" labyrinth(s) are positioned obliquely in front of sound producing transducer(s) to cause very wide angle dispersion of the sound waves projected from said transducer(s) into said labyrinths. The labyrinths may consist of a complex of bent and folded chambers. This system causes depolarization of the sound waves projected from the transducer(s).

Abstract: The acoustic transducer system includes an electroacoustic transducer and a flexural oscillator plate which is coupled to the electroacoustic transducer. The flexural oscillator plate is so constructed that at the system operating frequency it is stimulated to flexural oscillations of a higher order at which on the flexural oscillator plate node lines form between which antinode zones oscillating alternately in opposite phase lie. To influence the sound radiation of the flexural oscillator plate a sonic beam shaper is provided. The sonic beam shaper has soundwave barriers which are impermeable for soundwaves and which lie spaced from the flexural oscillator plate and acoustically decoupled therefrom in front of first antinode zones oscillating in equal phase with each other, and soundwave-permeable regions which lie between the soundwave barriers in front of the remaining second antinode zones oscillating in opposite phase to the first antinode zones.

Abstract: A directional microphone having an acoustic damping washer positioned about the microphone cartridge adjacent the microphone rear sound entry.