GB295625A - Improvements in or relating to sound reproducers - Google Patents

Abstract

295,625. Whitmore, W. B. Aug. 15, 1927, [Convention date]. Loud-speakers.-A sound reproducer comprises two diaphragms 21, 24 of different size marginally supported in spaced planes and connected together at their centres, and one or both membranes is made of inherently soft fabric coated with a non - hygroscopic material which forms a flexible film on drying, for example aeroplane dope. The diaphragm 21 is fastened to a frame 20 on the other side of which members 23 form a rectangle to which the other diaphragm 24 is secured. The diaphragms are drawn and secured together by nuts and washers 29 on a threaded rod 26, which is connected to the telephonic unit mounted on a bracket 32. According to modifications : the second diaphragm is replaced by a resilient strip (Figs. 5 to 6, not shown); the diaphragms are of equal size (Fig. 8, not shown); the diaphragms are connected together by a wire (Fig. 9, not shown); the diaphragms are connected together at a plurality of points (Fig. 10, not shown); three or more diaphragms are used (Fig. 11, not shown): the diaphragms are kept under tension by being held apart (Fig. 12, not shown); the tension of the diaphragm is maintained by coating the diaphragm with incompressible material while held under tension.