Abstract: The present invention relates to refractive stigmatic systems designed to deflect or focus elastic surface waves which can propagate at the surface of a substrate. The object of the invention is a lens or prism comprising an array of elementary refractive zones formed by deposition or ion implantation and intended to produce uniform attenuation of refracted vibrational radiation.

Abstract: A moving coil loudspeaker of the type including a pair of co-axial speech coils, one for driving a high frequency diaphragm at the rear of the loudspeaker to provide an output along a horn and the other for driving a cone forming a continuation of the horn and reproducing the lower frequencies has an acoustic lens fitted in the region where the horn contour is taken over by the cone, the lens being shaped over its external surface so as to conform snugly with the contour of the cone and being effective to increase the divergence of the beam of acoustic radiation from the horn in the operative plane of the lens. The acoustic lens is preferably so designed that the divergence of the acoustic beam from the horn matches that from the cone and may be of the slant-type, being held by a cruciform mounting extending across the mouth of the horn proper.

Abstract: There are disclosed radiation deflection method and means for controlling the direction of travel of radiation which is subject to refraction, such as light and sound radiation. The deflection method and means, which are particularly adapted for effecting a scanning motion of the radiation in one direction, include first and second generally counterrotating refracting wedges through which the radiation passes. The second wedge is mounted for rotation about a fixed axis and the first wedge is mounted for rotation about an axis which nutates about the fixed axis of rotation of the second wedge. Means are provided for rotating the first and second wedges in opposite rotary directions at equal angular displacements while simultaneously nutating said first wedge.

Abstract: Loudspeaker and stereophonic system employing hemicylindrical wave form generators, in which the vertical extent of the speaker includes and spans the levels of seated and erect standing listeners, approximating a floor to ceiling height. Two such speakers are placed in a room, directed toward each other and spaced from an end wall, with arc of sound emission of each such that the listener region receives direct sound and two first order reflections, from side and end walls, from each of the two speakers. The path lengths are shown different in length greater than the minimum separate-source discrimination time.

Abstract: A refracting structure with passages of different shapes with some separation of adjacent passages provides a minimum of sound reflections. It can be designed in the form of spherically divergent lenses with passages with cross sections in the form of squares or of concentric circular slits, a cylindrically divergent lens with slit shaped passages, and in other forms. Stagger of ends of the passages is discussed.