GB288276A - Improvements in sound producing and reproducing instruments - Google Patents

Abstract

288,276. Victor Talking Machine Co., (Assignees of Haigis, C. D.). April 6, 1927, [Convention date]. Loud-speakers; magnetic instruments; diaphragms. - An electromagnetically or mechanically operated sound producing or reproducing diaphragm is of conical or frusto-conical formation and has means located within the cavity of the diaphragm to cause the sound waves to travel in a direction substantially parallel to the surface of the diaphragm whereby interference due to radiation from different parts of the diaphragm is avoided. Fig. 1 shows a moving coil loud-speaker having a conical diaphragm 8, the periphery of which is attached to a ring U clamped between the flange 10 of a supporting-ring 7 and a ring 11. One or more gaskets 12 may be interposed between the flange 10 and the ring 9. The diaphragm is mounted opposite an aperture 16 in a partition 17 with a ring 18 interposed between the partition and the ring 11. The means for eliminating interference comprises a conical member 20 mounted within the cavity of the diaphragm upon brackets 21. The outer surface of the member 20 is parallel to the surface of the diaphragm and is arranged at such a distance from the diaphragm that no damping takes place. The member 20 may be hollow or solid and in the former case the inner surface may be parallel or tapered with respect to the outer wall. The inner end of the diaphragm carries the armature, moving coil or other means for driving the diaphragm and has a spider 13 attached by a screw 14 to the core 4 of the electromagnetic unit 1.