Talking moving picture system

Application filed October 31,

This invention relates to talking moving picture systems, and more particularly to a method of and means for reproducing the sound from a location coinciding with the 5 visual source thereof moving about the picture screen.

One of the present defects of certain talking moving picture systems is that the location of the source of sound in the reproducing 10 process is fixed. This tends to destroy the illusion as the spectator is impressed by the fact that the apparent location of the voice, does not coincide with the mouth of the moving figure thrown on the screen. The pri16 mary object of the arrangements of the invention is to overcome this defect. ' Other objects and features of the invention will appear more fully from the detailed description thereof hereinafter given.

The invention may be more fully understood from the following description, together with the accompanying drawings, in the Figures 1,2, and 3 of which the invention is illustrated. In Fig. 1 is shown a circuit 25 diagram of the recording process of the invention. Fig. 2 is a diagram of the sound reproducing arrangements. Fig. 3 is a diagram showing in more detail a portion of the arrangements of the reproducing mecha30 nism. Similar reference characters have been utilized to denote like parts in all of the figures.

In the recording arrangements of Fig. 1, there is shown a camera C. At the extremes 89 of the field or range of the camera are placed four microphones. The microphones M, and M₃ may be placed at the vertical extremes of the field of the camera and. the microphones M₂ and M₄ at the horizontal ex40 tremes.

The output of each microphone is connected to an amplifier, such as the amplifiers A„ A., A.,, and A._P The output of amplifier At will be connected to an amplifier r ⁴⁵ Ag and thence to a recorder R5 for making a record of the sound. The method of recording the sound by device R5 may be any desirable one, such as the phonographic method or the film method. The output of each of ⁶⁰ the microphones and amplifiers· Aj, A2, A_s,

PICTURE SYSTEM , 1928. Serial No. 316,238.

and A₄ is passed through a detector and then a low pass filter having a cut-off of about 10 cycles. The detectors are shown schematically as Di, D₂, D₃, and D₄. The low pass filters are shown schematically as F₁₅ F_2j F₃,

H and F₄. From each detector there is obtained a low frequency wave whose instantaneous value depends on the signal strength picked up by the microphone associated therewith. The four low frequency waves are then re- ¢0 corded at the same time and preferably in the same way as the voice, by recorder devices Ri, R₂, R₃, and R₄. The sensitivity of each of-the recording arrangements should be the same.

It is pointed out that in the process of recording as the source of the sound moves about in the field of the picture, the relative strength of the voice waves received by the four microphones varies. As the sound 70 moves from left to right, the sound waves received by microphone M₂ increase in strength. Those received by M₄ decrease. Similarly, if the source of sound moves in a vertical direction, the relative strength of 75 the sound wave reaching M_x and M_s varies. Accordingly, the strength of the sound records made by devices R_x, R,, R₃, and R₄ will be continually varied in accordance with the movement of the source of sound about the 80 field of the camera.

In the arrangements for reproducing the picture, as shown in Figure 2, a solid screen 12 is employed capable of reflecting sound waves. A single loud speaker 11 is also em- 8T> ployed. This loud speaker is assumed to have decided directional properties and to be pointed at the screen. The loud speaker is movable about two axes at right angles to each, other, such as a—a and δ—b. The 90 sound wave is produced from the record made by the recorder device R₅ and transmitted to the loud speaker 11. The motion of the loud speaker 11 about the twO axes is determined in the following manner. The four low fre- 93 quency waves as recorded by devices R_x, R₂, R_s, and R₄ are reproduced and transmitted tq the amplifiers A/, A/, A₃', and A/. The low frequency wave from recorder R_x will be transmitted to amplifier A/; the wave from ¹⁰⁰

1,860,180 recorder K₂ to A/; that from R₃ to A₃'; that from E; to A/. The outputs from amplifiers A/ and A_s' are connected to a selfbalancing bridge arrangement in which the galvanometer 1 rotates if there is a difference of volume from the two amplifiers, and at the same time adjusts a ratio arm 5 to balance the arrangement. When a balance is obtained no current flows through the galvanometer. This adjustment takes place very rapidly so that if the relative strength of the low, frequency signal from the two records made from microphones Mi and M₃ varies, the galvanometer follows the change with corresponding adjustments. In thus moving, the galvanometer 1 also switches a contact arm 7, carrying a ground connection over a group of. contacts connected to leads designated 9. In a similar manner the low fre20 quency records derived from microphones M₂and M₄ are caused to actuate a self-balancing galvanometer 2 having a ratio arm 6 and a contact arm 8 with grounded connection, which moves over a group of contacts con²⁶ nectfed to leads designated 10.

The leads 9 are designed to control the rotation of the loud speaker 11 about the axis a—a, and the leads 10 are designed to control the rotation of the loud speaker 11 about the axis δ—δ. This will appear more fully from the diagram shown in Fig. 3. In Fig. 3, the loud speaker 11 is shown mounted upon the member 13. This member 13 rotates about the axis Or-a. The rotation of member 13' audible record, and means about this axis is controlled by a series of magnets, such as 14,15,16, and 17, arranged to be diagonally opposite each other on the circular member 19. For example, if the. grounded contact arm 7 engages one of the leads 9, as shown, a circuit will' be completed to battery 18, which will energize the diagonally opposite magnets 14 and 16. This will attract the pole pieces of member 13 and rotate the loud speaker 11 about the axis aIf the grounded contact member 7 should move to the next succeeding lead, the. circuit would be completed from battery 18, energizing diagonally opposite magnets 15 and 17 and thereby change the position of loud speaker 11 about the axis a—a. The loud speaker 11 is mounted on the flat circular member 19 in such a way that it may be rotated about the axis δ—δ when the circular member 19 rotates about such axis. . This rotation is controlled by a series of diagonally opposite magnets, such as 21 and 22, mounted on a spherical member 20. The .pole pieces of member 19 are shown positioned with respect to magnets 21 and 22. When the grounded contact arm 8 is in contact, as shown with one of the leads 10, the .circuit is completed from battery 23, energizing the magnets 21 and 22 to control the rotation of the loud speaker 11 about the axis δ—δ. Other diagonally opposed magnets, not shown, are arranged in similar fashion on the spherical member 20 and energized by succeeding ones of the leads 10 to further control the rotation of member 19 and loud speaker 11 about the axis δ—δ. 70

As a result of the combined movements about the two axes, the sound is thrown against the screen at a point which moves about in a manner corresponding to the move ment of the object which produced the sound 75 in the original recording process. The sound is then reflected from the screen to the spectator and appears to originate from the proper location.

While the invention has been disclosed as 80 embodied in- certain specific arrangements which are deemed desirable, it is understood that it is capable of embodiment in many other widely varied forms without departing from-the spirit of the invention as defined by the. appended claims. _s