Abstract: A loudspeaker system has one or more drivers having their back side connected to a duct that is open at the top end and closed at the bottom end. A diverter is attached to the back side of each driver to deflect its back output wave approximately 90 degrees toward the open end of the duct. A pair of woofers are arranged back-to-back and joined together at the bottom of the duct, the front side of each woofer adjacent an opening in the duct. A port aperture is provided at a vertical location in the duct to provide a null at that location. The front wave of the drivers is directed toward the listener and the back wave is directed toward the ceiling, spreading out and down into the room, to be met by the front wave; the opposite phases canceling, eliminating excitation of room resonances and reflections.

Abstract: A single-sleeve valve engine has narrow quasi-elliptic sleeve motion which improves exhaust and intake valving and permits the conversion of standard engine blocks. The sleeve is thick walled, and is molded of low density material which permits significant rounding of the sleeve apertures for better flow, and grooves and rings for oil control, gas leakage reduction, and mass reduction. The sleeve has an extension which projects above the head and is connected to a half-speed crankshaft by means of a connecting rod. This connecting rod is restrained at an intermediate point by a radius rod to obtain quasi-elliptic sleeve motion which has an amplitude approximately half as great circumferentially as axially. In order to minimize emissions, provision is made for swirl, scavenging, multiple spark plugs, and a near ideal combustion chamber shape.