Abstract: The present invention relates to a motor vehicle mounted directional microphone assembly for use in hands-free cellular telecommunications. The microphone assembly is comprised of a case and a removable directional microphone module. The case is adapted to mount and lock the module in a plurality of different orientations, thereby enabling the assembly to accommodate various mounting arrangements within the vehicle. The module is releasable, however, from its locked position to permit re-orientation of the microphone with respect to the case, if desired. The module is also completely removable from the case to permit mounting of the module within the vehicle in mounting arrangements independent of the case.

Abstract: A directional dynamic microphone includes a protective cover, a diaphragm in air-tight engagement with the cover, a voice coil, and a magnet with a core pole member and a tubular pole member and disposed rearwardly of the diaphragm. The magnet has an outer front circumferential portion which is spaced apart from an annular wall of the cover to confine a sound passage therebetween, an outer intermediate circumferential portion which engages the annular wall and which defines a sound port opening outwardly and radially for air communication with the sound passage, and an outer rear circumferential portion with sound holes angularly displaced therein and smaller than the sound port. Each sound hole extends inwardly and radially for air communication with a rear major side of the diaphragm. A phase shift effecting sheet veils the sound port so as to impart the microphone with a unidirectional characteristic.

Abstract: An acoustic mechanism is provided for a microphone, by which the transmission sensitivity-vs.-frequency characteristic of the microphone can be adjusted by an easy operation. Good communication quality can be thereby invariably secured for radio communications, and a preferred communication sound can also be obtained.

Abstract: A microphone array for providing a focused field of optimum audio reception is disclosed. The array has a series of interconnected microphones spaced within a housing. At a midpoint of the spaced microphones is an illuminated polarized centering marker which gives the user a visual signal that the user is located within the optimum filed of audio reception. The housing can be placed on the top front edge of video monitor and has slideably mounted removable feet, which allow the microphones to be aimed more accurately at the user. The array is foldable along a midpoint, which allow for compact storage. The folding mechanism is a hinge, which has a hollow core, and openings which allow the internal wiring to interconnect two wings of the array without exposing the wires. The wings are held in their longitudinally oriented position by a latching mechanism of pins in one wing which snap fit into capture boots within the other wing.

Abstract: The present invention relates to a directional microphone, in particular having symmetrical directivity, having an interference tube with a tube axis which is provided with a row of sound inlets arranged at least approximately parallel to tube axis, and which incorporates an electroacoustic transducer in its inside in the vicinity of its rear end face. It is further provided that the row of sound inlets is arranged non-symmetrically to tube axis opposite the outer periphery of interference tube.

Abstract: A monolithic second order gradient (SOG) microphone structure employs acoustic transmission lines wherein the acoustic phase delay along each of the acoustic transmission lines is in direct proportion to the length of each of the acoustic transmission lines and, where this is effected by the use of an acoustic impedance element placed within each acoustic transmission line that has an acoustic impedance related to the acoustic impedance of the associated acoustic transmission line. In one embodiment, the acoustic impedance element has a specific acoustic impedance substantially matched to the specific acoustic characteristic resistance of the acoustic transmission line. Various embodiments may utilize acoustic or electrical subtraction of the signals in the acoustic transmission lines to realize the desired directional sound pickup.