Abstract: A system for receiving a plurality of audio input signals encoded with sound directions drives a plurality of loudspeakers which are physically arranged to generate apparent sound images in relation to encoded sound directions. The encoded input signals are analyzed for determining whether one encoded sound direction exceeds a predominance threshold with respect to other encoded sound directions. Logic control signals are generated for indicating directionality of predominant sound directions. In response to generated logic signals, the directional stability of the apparent sound images is enhanced.

Abstract: An arc furnace and investment casting apparatus includes a copper base with an integrally formed crucible having a passage therethrough. A vacuum chamber is positioned on the top of the copper crucible with a non-consumable cathode projecting into the chamber to effect melting of metal placed in the crucible. A vacuum chamber is also suspended beneath the crucible for support of a mold to receive molten metal flowing through the passage.