Patent GB-388409-A (GB)
Title: Improvements in or relating to the simultaneous reproduction of sounds and pictures
IPC: H04R3/12
Filed: 1931-05-20
Abstract: 388,409. Reproducing music. DUBILIER CONDENSER CO. (1925), Ltd., Ducon Works, Victoria Road, North Acton, London.-(Assignees of Linke, J. ; 65, Niebuhrstrasse, Charlottenburg, Berlin.) May 20, 1931, No. 14856. Convention date, May 20, 1930. [Class 40 (iv).] Apparatus for the simultaneous reproduction of sounds and pictures comprises two or more loud-speakers B, F, each of which is adapted to reproduce sounds having separate sources of origin during recording, and one of these loudspeakers is movably disposed at the rear of the picture screen A so that it may be caused to take up appropriate positions according to the movements of the character or characters depicted on the screen. Two loud-speakers F may be disposed in a fixed position at the foot of the screen for the purpose of reproducing accompanying sounds, such as an orchestral accompaniment. A record of the necessary movement of the loud-speaker B is made during recording of the sounds by dividing the picture into several fields or squares and directing a spot light on to a sound control strip at a point in the same relative field as that in which the actor appears in the picture. This control strip is adapted to co-operate with a number of photo-electric cells, one cell being provided for each field or square, for controlling, by means of relays, motors C, D for moving the loudspeaker B horizontally and vertically. The horizontal movement of the loud-speaker may be effected by worm gearing or by a cable over a pulley, and the effect of bringing a particular photo-electric cell into action is to set the motor into operation for a sufficient time to move the loud-speaker into the next square. It is arranged that for movement of the loudspeaker into the adjacent right-hand square, thc action of the photo-electric cell sets up a certain impulse to operate the motor, whilst for movement of the loud-speaker into the adjacent left-hand square, the appropriate photo-electric cell causes a different impulse to be imparted and the actuation of a switch on the motor so that the latter is put into reverse. Alternatively, the loud-speaker B may be moved horizontally by a cable secured between a winding drum on the motor and a spring drum, and either of these drums is adapted to operate according to the direction in which the loud-speaker is to be moved. The loud-speaker is moved vertically by a spindle driven from the motor D. The picture is projected on to the screen by means of apparatus G which at the same time operates the sound-control strip and the sound records associated with the loudspeakers B, F as shown in Fig. 2. A separate amplifier K may be provided for the loudspeaker B and the loud-speakers F, or a single amplifier having several tuned circuits may be employed. The picture film may be combined with the sound records, but the sound control strip is preferably separate. During recording, the sounds representing the accompaniment of a soloist may be recorded separately behind a sound-proof partition with respect to the position of the soloist, and this partition may be transparent. The Specification as open to inspection under Sect. 91 describes also the loud-speaker B as fixed in position when the picture screen is of small size. This subject-matter does not appear in the Specification as accepted.