ES335168A1 - Speaker System. - Google Patents

Abstract

A speaker system has two spaced, coaxially mounted cone-type low-frequency speakers of the type producing front and rear waves of acoustic energy connected such that their diaphragms move in the same direction at any given instant. An open baffle of sound opaque material is joined, acoustically tight, to each of the speakers. The speakers are enclosed in cloth. A speaker 42 (Fig. 1) has its magnet structure secured by thumb screws 43 in a socket 44 at the top of a pedestal 45. A lead shell 46 with an aperture 47 for the speaker 42 is lined with sound-absorbing material 48. A similar lead shell 49, lined with sound-absorbing material 55 and having a central aperture 56, is secured between a spider 50 and the mounting flange of a smaller speaker 51. Acoustic cloth 59 is supported by a wire frame 60 which rests on the magnet of speaker 51 and the upper edge of the shell 49. The shells 46, 49 are substantially cylindrical. Alternatively, the shells may be polygonal (Figs. 4 to 6, not shown), e.g. rectangular, and have corrugations and irregularities. The side walls may curve gently and the corners follow an exponential path. In order to supplement the upper frequency range, two smaller speakers (73, 74) are mounted coaxially in much the same way as the larger speakers except that they are not supplied with baffles. The smaller speakers (73, 74) are supported between wire frames (76, 77) above the larger speakers, and acoustic cloth (78) surrounds the frame (77). The smaller speakers (73, 74) are energized in phase with one of the larger speakers, filter or cross-over networks being incorporated where required. Alternatively, (Fig. 7, not shown), baffles (80, 81) are given a different profile so as to be accommodated in a tapering frame (82) and acoustic cloth enclosure (83). For ceiling mounting (Fig. 8), the structure of Fig. 7 is used, inverted and truncated. A frame (90) supports high frequency speakers (79) below the larger speakers. In a further arrangement, identical speakers (92, 93), Fig. 9 (not shown), with bowl-like baffles (94, 95) are joined by studs (12). The baffles (94, 95) are identical, being formed from sheet lead lined with sound-absorbing material (98). A cylindrical acoustic cloth (96) and a pedestal provide a construction similar to a table lamp. Instead of lead, the baffles may be of glass wool, felt, cork acoustic " Celotex" (Trade Mark) expanded polystyrene or foam rubber.