GB319399A - Improvements in or relating to gramophones and like sound-reproducing machines - Google Patents

Abstract

319,399. Cullum, H. J. June 21, 1928. Cases with internal horns.-The cabinet of a gramophone or like sound reproducing machine is constructed with hollow side walls, the inner members 11 of which are adapted to form side sounding boards constituting the side walls of a flared sound outlet chamber arranged as an extension of the sound-amplifying horn. The outlet end of the horn is supported mainly or wholly by " dumb bars " 12 fixed to the side sounding boards 11. The horn is constructed of a plurality of sections 6, 7, 8 made of different materials, for example the first section 6 may be of brass, the second section 7 of a thinner gauge metal such as zinc, and the third section of terne plate. The " dumb bars " 12 may be formed with a slot 13, Fig. 5, for the reception of the corresponding edge of the flared outlet 9 of the horn, and felt 14 may be interposed in the joint. The bars 12 may be secured to the boards 11 by screws 15. The upper wall of the extension chamber may consist of an inclined sound board 19 extending upwardly from the front upper edge of the horn outlet to the top of the sound outlet 20, and the sides of such board may be left free and have felt applied to them. The boards 11 may be formed of plywood. Apertures 22 may be provided in the side boards 11, or the side sound chambers may be open at the bottom or at the outer sides. Fig. 4 represents a sectional plan.