Abstract: A method and apparatus for color screening combines existing halftone pixel matrices into a super cell. Images of different intensities are displayed using such a super cell by selectively illuminating pixels in the super cell in an order that depends both on the illumination order of the original cells and a visitation order for the halftone cells that make up the super cell.

Abstract: The invention provides a device for collecting the exhaust gas jet of an aircraft reactor with orientable propulsion nozzle or with a gas jet orientable with respect to the longitudinal axis of said reactor, during ground testing of the latter, as well as a testing installation for aircraft reactors equipped with said device. The device comprises an external cylindrical jacket bell-mouthed at its end intended to be situated opposite the tested reactor and a cylindrical internal jacket, concentric to said external jacket and intended for straightening out the exhaust gas jet when this latter or the propulsion nozzle of the tested reactor has a slant with respect to the axis of said reactor.

Abstract: An acoustic liner comprising a sound permeable inside plate forming a first closed annulus, and a sound impermeable outside plate forming a second closed annulus located outside of and extending around the first closed annulus. The inside and outside plates are spaced apart and thus form an annular chamber therebetween; and a core member is secured in this annular chamber, between the inside and outside plates. The core member forms or has the shape of a sine wave form annularly extending around the inside plate, and the core member and the inside plate form a multitude of varying depth sound absorption chambers to attenuate sound waves over a broad band of frequencies.

Abstract: A headset is provided which includes an inverted cup-shaped housing. The housing contains a rigid membrane which separates the housing into an upper chamber and a lower chamber. An inertial transducer is positioned in the upper chamber secured to the membrane. Electrical leads extend into the transducer through water tight connections. A headband is provided to secure the headset to a listener's ear and a cushion is provided about the open bottom end of the headset housing. Only the transducer itself is water tight. Both the upper and lower chambers of the housing freely permit the passage of water.

Abstract: Method of reducing the overflying noise of airplanes having a propeller den by a piston engine. The propeller is arranged on the engine shaft in such a way that positive components of the engine sound pressure fall on negative components of the propeller sound pressure. It is preferable to use an engine/propeller combination in which the number of engine ignitions per revolution of the propeller shaft divided by the number of the propeller blades is an integer, preferably being equal to 1.

Abstract: A vocal sound muffling device having an elongated tubular body providing an elongated tubular cavity, a mouthpiece on one end of the body providing an inlet into the cavity for vocal sound waves and atomized fluids, a closure on the other end of the body having a fluid outlet therein for regulating fluid flow from the cavity, and cellular material in the cavity intermediate the inlet and outlet for attenuating the vocal sound waves.

Abstract: An acoustical voice tube, comprising an acoustical hollow upper piece and an acoustical hollow lower piece in hinged connection permits voice or sound tube positioning over a large area without changing the sound characteristics.

Abstract: A loudspeaker system is provided for installation in a space between a front panel and an enclosed area behind the front panel of a partition such as a wall, ceiling or floor fronting a listening area. Electroacoustical transducers are provided which have a two sided vibratory diaphragm driven by an electrical signal. An enclosure mounts the electroacoustical transducers such that one side of the vibratory diaphragm is in contact with air outside the enclosure, with the enclosure being configured to substantially enclose and define a specific volume of air within the enclosure having a predefined acoustic compliance and which is in contact with the other side of the vibratory diaphragm of the electroacoustical transducers.

Abstract: A muffler has a muffler body within which is located an intermediate duct pipe colinear with the exhaust and tail pipes, so that exhaust gas from the exhaust duct pipe can pass through a main flow route in the intermediate duct pipe in a substantially straight line without reflecting. An inner or by-pass pipe forms a gas by-pass and has gas flow restriction elements.

Abstract: An enclosure for a bass loudspeaker for housing in a larger multiple loudspeaker enclosure having a pair of concentric cylindrical shells filled with dense particulate matter.

Abstract: A heating device, particularly an automotive heating device, in which a noise muffling device is integrated within the heating device. The muffler can be provided in the combustion pipe defining the combustion chamber, or the combustion pipe, itself, can be designed as the muffler. The muffler operates by absorption and/or reflection sound muffling techniques in accordance with various embodiments, and may, simultaneously, purify the combustion gases, for example, by catalytic afterburning, and/or by filtering of soot particles. The muffler is arranged in a hot zone, but not in the flame area of the combustion chamber, to achieve a self-cleaning action. In other embodiments, noise muffling material is arranged in an exhaust gas collection chamber to achieve sound muffling based on reflection and/or absorption and/or other conventional sound reduction methods. In all cases, the need for an external muffler in the exhaust line from the heating device is eliminated.

Abstract: For the purpose of muffling low-frequency sound waves such as occur in components of fluid-flow engines, the muffler proposed here consists of a feed pipe (1) through which (3) and around which (4) a medium flows. At its end in the direction of flow, the feed pipe (1) has a row of muffling bore holes (2) distributed over the periphery, via which the medium (4) flowing around the feed pipe (1) flows into the interior of the feed pipe (1). The effective length L of the feed pipe (1), the cross-sectional area A of the feed pipe (1) and the total cross-sectional area B of the muffling bore holes form the geometric parameters for calculating an optimum muffling of the low-frequency sound waves.

Abstract: A device for assisting a computer operator in the use of computer programs includes relatively movable cards bearing data areas thereon arranged in such a way that the operator can, firstly, by visual inspection, readily locate the desired operation to be performed by the program and, secondly, by moving the cards relative to one another, obtain, for that desired operation, information regarding the command to be entered into the computer.

Abstract: A combination hubodometer protective housing and step assembly having a cylindrical metal housing, to which the hubodometer is mounted, and a cylindrical metal adapter, which couples the housing and hubodometer to the axle of a wheel for rotation therewith. The housing and the adapter, and hub assembly and the adapter are coupled by means of threads along the inner and outer surfaces. The hubodometer is mounted to an internal wall of the housing by a threaded stud and nut. The internal wall of the adapter defines an internal chamber which contains lubricant for the vehicle axle. Excess lubricant is allowed to exit the lubricant chamber through vent holes in the housing and step assembly.

Abstract: A speaker is installed on a door panel of an automobile by utilizing a supporting unit including a base and a substantially disc-shaped spacer. The base is attached to the door panel and has a bottom surface inclined with respect to the door panel. The speaker is secured to the inclined bottom surface of the base by an attachment screw, between which the spacer is interposed. The spacer has an inclined surface adapted to be in contact with the inclined bottom surface of the base. The spacer is provided with a half-round groove through which a screw extends to secure the spacer to the base at a desired position relative to the latter within an range of 180.degree. rotation. The inclination of the base is amplified or counterbalanced by the inclination of the spacer in dependence with relative position therebetween to vary the orientation of the speaker supported on the opposite surface of the spacer.

Abstract: A readily removable and replaceable acoustical absorber for mounting in a channel that utilizes a flexible grid within the absorber to support the absorber on flanges of angles mounted on the channel walls.

Abstract: An ear tip for use with a stethoscope, audio headset or like device, the ear tip being of a construction and design that provides substantial deformation of the ear tip under normal stethoscope pressures such that in use the ear tip is seated comfortably and conformably against the ear canal opening.

Abstract: A muffler includes a first expansion chamber, a second expansion chamber, a resonator chamber and an inlet pipe having a first open end and a second open end. The first open end of the inlet pipe is inserted into the first expansion chamber so as to communicate with the first expansion chamber. A resonator pipe runs substantially in coaxial relationship with the inlet pipe so as to establish communication between the first expansion chamber and the resonant chamber. A return pipe is disposed between the resonator chamber and the second expansion chamber and passes through the first expansion chamber for establishing communication between the first expansion chamber and the second expansion chamber. An outlet pipe communicates with the second expansion chamber. Said return pipe is inserted with the open end into said resonator chamber, while the inserted open end of the return pipe is furnished with a plug. A portion of the return pipe passes through the first expansion chamber.

Abstract: A device for keeping score during a scoring game and, in particular, during a game of golf. A plurality of counting beads having respective passages formed therethrough are strung in a serpentine manner on respective first and second portions of a string, such that the first and second portions of string overlap one another in the passage of each bead. Score is kept by selectively sliding the beads along the length of string to a desired position, wherein they are maintained in place by the string.

Abstract: A noise suppression system for use with a jet aircraft engine having a plug support cylinder affixed to the engine, a tubular ejector shroud affixed to the engine and encompassing the plug support, the shroud having a reduced internal diameter adjacent the aft end and a plurality of spaced apart blow-in openings formed circumferentially about the shroud forward end providing passageways for the entrance of ambient air from the exterior to the interior of the shroud. A blow-in door is secured to the shroud for opening and closing each of the blow-in openings. A translating plug is supported on the plug support cylinder and is positionable between a forward position and an aft position and forms an annular exhaust nozzle between the exterior of the plug and the interior of the aft end of the shroud. A daisy mixing nozzle is positioned within the shroud aft of the blow-in doors, the nozzle being configured of a plurality of lobes providing undulating interior and exterior surfaces.