Abstract: Monophonic sound is transformed into a stereo pattern by arranging two reflectors on a common axis at a predetermined distance from each other with both facing in the direction of the sound. One reflector has a larger diameter than the other and is provided with a central aperture into which a tone generator is mounted and spaced from the smaller reflector.

Abstract: A unique index mechanism for positioning an indexable machine tool member wherein a first toothed coupling is fixed to a machine tool base member, and a second relatively movable, toothed coupling having a uniformly spaced number of teeth unequal to the first uniformly spaced coupling teeth is located concentric to the first coupling on the machine tool base. The indexable machine tool member is carried by the second movable coupling, and a third toothed coupling with teeth disposed toward the first and second couplings is rotatably mounted to the machine tool in such fashion that the third coupling may be powered into and out of meshing engagement with the first and second couplings.The second coupling which carries the indexable machine tool member may be indexed to discrete angular increments corresponding to the angular difference in the tooth spacing of the respective first and second couplings.