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.

Abstract: An attachment for a phonograph pickup cartridge capable of removing static and stabilizing vibration of the cartridge body. A brush comprising bristles capable of engaging the inside of the grooves of a disc-type phonograph record is coupled to the cartridge body through a bearing which provides a mechanical resistance capable of damping both vertical and lateral vibrations. The brush is made from an electrical conductor, such as carbon, and is connected to the shield of the cartridge to remove static electricity from the surface and grooves of the record.

Abstract: An apparatus and process for removing undesired monomers and oligomers from polyamide melt at subatmospheric pressure by passing steam through the melt to absorb the undesired components and carry them away. Various constructions are disclosed for vigorously intermixing the gas with the melt in which the gas is passed through a foraminous surface over which a thin film of melt flows, and a rotating agitator, spaced less than 50 mm from the surface, mixes the gas with the melt film. In a preferred form of the invention the rotating shaft comprising the agitator carries screw threads and serves as a conveyor for discharging treated melt from the pressure vessel in which the process is carried out.