Abstract: A voice enhancer system for a car includes a pair of microphones positioned adjacent to the front seats of the car, and a pair of loudspeakers positioned adjacent to the rear seats. The microphones are connected to the loudspeakers, via an amplifier/electrical conditioning unit, by electrical wiring positioned behind the car's upholstery. The conditioning unit, which includes filters and a frequency shifter is adjusted to prevent acoustical `howl-around` within the enclosure of the car. For voice enhancement from the rear to the front of the car, microphones may be positioned adjacent to the rear seats, and loudspeakers may be positioned adjacent to the front seats, these components being connected together, via a second amplifier/electrical conditioning unit, by electrical wiring.

Abstract: The specification discloses a method of anchoring sheet material to a framework constituted by a pair of spaced apart frame members. A respective edge of the sheet is slidably engaged in a groove in each of the frame members in such a manner that the sheet cannot be removed laterally therefrom. The sheet material is stretched by pulling another edge portion of the sheet and anchoring said edge portion with the sheet in a stretched condition.

Abstract: A joint for connecting together three generally tubular members comprises first and second members and a clamp for joining the two joint members together. Each of the joint members has first and second portions, the first portion of each joint member being a telescopic fit within a respective one of the tubular members. The second portions of the two joint members together form a connector when the joint members are juxtaposed. The clamp is effective to pass around the two second portions of the juxtaposed joint members to fix the connector for coupling a third tubular member.

Abstract: A building structure is made up from a framework covered by sheet material. The building structure has a generally rectangular floor plan. The framework has two end structures and a main body portion composed of a plurality of interconnected parallel arches which extend at right-angles to an axis of symmetry of the floor plan of the building structure. The sheet material is connected to the framework under tension so as to increase the strength of the finished building structure.