Abstract: Planar magnetic transducers including diaphragms having electrical conductors thereon which are mounted within frames so that spaced magnets are disposed on opposite sides of central sound producing surface areas of the diaphragms. Pole elements are provided in spaced relationship between each of the magnets and extend inwardly toward the diaphragms so to form pole extensions for causing magnetic flux from the poles of the magnets proximate to the diaphragms to extend more densely and generally parallel to the electrical conductors between the magnets and the pole elements. Openings for acoustic waves are provided between the pole elements and adjacent magnets.

Abstract: An electromagnetic transducer is disclosed wherein separate elongated strips of magnetic material are secured on both sides of a plane containing a flat flexible insulating thin-film diaphragm. Conductors attached to the diaphram extend primarily parallel to the magnetic strips and cause movement of the diaphram when excited electrically. The conductors can also deliver current induced by diaphram movement within the field. The magnetic strips are fastened to a frame that clamps the perimeter of the diaphram. The sub-assemblies containing the magnetic strips provide maximum available area for the propagation of acoustic waves to and from the environment and provide increased flux density.

Abstract: An air bearing straight line tracking phonograph tonearm combines the features of a readily removable decoupled counterweight arm which bears horizontally and vertically adjustable counterweights; a readily removable tonearm tube with tapered wall thickness having an integral headshell, cartridge and stylus; various simple means for vertical and leveling adjustments; and a vertical tracking angle or stylus rake angle control that automatically retains perfect tracking tangency.