GB830081A - Improvements in or relating to electro-mechanical transducers for use in sound recording or reproducing systems - Google Patents

Abstract

830,081. Phonograph recorders and reproducers. TELEFUNKEN G.m.b.H. June 20, 1956 [June 21, 1955], No. 19038/56. Class 40 (4). In a stereophonic sound system in which two separate signals are recorded simultaneously in a single groove 2 of a disc or tape record 1 as lateral and hill and dale oscillations, the recording and reproducing apparatus comprises two separate transducers for the two kinds of oscillation which are connected to a common stylus 3 by a mechanical linkage arranged to decouple the transducers one from the other. In one arrangement, Fig. 1, two moving-coil transducers 6, 7 pivoted in mutually perpendicular planes a-b, c-d are coupled to the common stylus 3 by flat leaf-springs 4, 5, the compliance of the springs in their pivotal planes effectively associating the transducers 6 and 7 with lateral, and hill and dale stylus oscillations respectively. An alternative arrangement, Fig. 2, comprises two transducers enclosed in housings 8, 9 from which vibrating members or armatures 10, 11 project. The stylus is carried by a cranked carrier 12 which has three pivot points in the planes e-f and g-h, two pivots contacting the armatures 10 and 11 while the third engages one end of a rod supported by a plate 13. The Specification mentions the use of moving iron, electrostatic, piezo-electric and variable-resistance type transducers.